My background is marble. Note that the rule for the BODY element will work even though the BODY tag has been omitted in the HTML source since the HTML parser will infer the missing tag. Backgrounds of elements that form a stacking context (see the 'z-index' property) are painted at the bottom of the element's stacking context, below anything in that stacking context. 14.2.1 Background properties: 'background-color', 'background-image', 'background-repeat', 'background-attachment', 'background-position', and 'background' 'background-color' Value: | transparent | inherit Initial: transparent Applies to: all elements Inherited: no Percentages: N/A Media: visual Computed value: as specified This property sets the background color of an element, either a value or the keyword 'transparent', to make the underlying colors shine through. Example(s): h1 { background-color: #F00 } 'background-image' Value: | none | inherit Initial: none Applies to: all elements Inherited: no Percentages: N/A Media: visual Computed value: absolute URI or none This property sets the background image of an element. When setting a background image, authors should also specify a background color that will be used when the image is unavailable. When the image is available, it is rendered on top of the background color. (Thus, the color is visible in the transparent parts of the image). Values for this property are either , to specify the image, or 'none', when no image is used. Example(s): body { background-image: url("marble.png") } p { background-image: none } Intrinsic dimensions expressed as percentages must be resolved relative to the dimensions of the rectangle that establishes the coordinate system for the 'background-position' property. If the image has one of either an intrinsic width or an intrinsic height and an intrinsic aspect ratio, then the missing dimension is calculated from the given dimension and the ratio. If the image has one of either an intrinsic width or an intrinsic height and no intrinsic aspect ratio, then the missing dimension is assumed to be the size of the rectangle that establishes the coordinate system for the 'background-position' property. If the image has no intrinsic dimensions and has an intrinsic ratio the dimensions must be assumed to be the largest dimensions at that ratio such that neither dimension exceeds the dimensions of the rectangle that establishes the coordinate system for the 'background-position' property. If the image has no intrinsic ratio either, then the dimensions must be assumed to be the rectangle that establishes the coordinate system for the 'background-position' property. 'background-repeat' Value: repeat | repeat-x | repeat-y | no-repeat | inherit Initial: repeat Applies to: all elements Inherited: no Percentages: N/A Media: visual Computed value: as specified If a background image is specified, this property specifies whether the image is repeated (tiled), and how. All tiling covers the content, padding and border areas of a box. The tiling and positioning of the background-image on inline elements is undefined in this specification. A future level of CSS may define the tiling and positioning of the background-image on inline elements. Values have the following meanings: repeat The image is repeated both horizontally and vertically. repeat-x The image is repeated horizontally only. repeat-y The image is repeated vertically only. no-repeat The image is not repeated: only one copy of the image is drawn. Example(s): body { background: white url("pendant.png"); background-repeat: repeat-y; background-position: center; } A centered background image, with copies repeated up and down the padding and content areas. [D] One copy of the background image is centered, and other copies are put above and below it to make a vertical band behind the element. 'background-attachment' Value: scroll | fixed | inherit Initial: scroll Applies to: all elements Inherited: no Percentages: N/A Media: visual Computed value: as specified If a background image is specified, this property specifies whether it is fixed with regard to the viewport ('fixed') or scrolls along with the containing block ('scroll'). Note that there is only one viewport per view. If an element has a scrolling mechanism (see 'overflow'), a 'fixed' background does not move with the element, and a 'scroll' background does not move with the scrolling mechanism. Even if the image is fixed, it is still only visible when it is in the content, padding or border area of the element. Thus, unless the image is tiled ('background-repeat: repeat'), it may be invisible. In paged media, where there is no viewport, a 'fixed' background is fixed with respect to the page box and is therefore replicated on every page. Example(s): This example creates an infinite vertical band that remains "glued" to the viewport when the element is scrolled. body { background: red url("pendant.png"); background-repeat: repeat-y; background-attachment: fixed; } User agents that do not support 'fixed' backgrounds (for example due to limitations of the hardware platform) should ignore declarations with the keyword 'fixed'. For example: body { background: white url(paper.png) scroll; /* for all UAs */ background: white url(ledger.png) fixed; /* for UAs that do fixed backgrounds */ } See the section on conformance for details. 'background-position' Value: [ [ | | left | center | right ] [ | | top | center | bottom ]? ] | [ [ left | center | right ] || [ top | center | bottom ] ] | inherit Initial: 0% 0% Applies to: all elements Inherited: no Percentages: refer to the size of the box itself Media: visual Computed value: for the absolute value, otherwise a percentage If a background image has been specified, this property specifies its initial position. If only one value is specified, the second value is assumed to be 'center'. If at least one value is not a keyword, then the first value represents the horizontal position and the second represents the vertical position. Negative and values are allowed. A percentage X aligns the point X% across (for horizontal) or down (for vertical) the image with the point X% across (for horizontal) or down (for vertical) the element's padding box. For example, with a value pair of '0% 0%',the upper left corner of the image is aligned with the upper left corner of the padding box. A value pair of '100% 100%' places the lower right corner of the image in the lower right corner of the padding box. With a value pair of '14% 84%', the point 14% across and 84% down the image is to be placed at the point 14% across and 84% down the padding box. A length L aligns the top left corner of the image a distance L to the right of (for horizontal) or below (for vertical) the top left corner of the element's padding box. For example, with a value pair of '2cm 1cm', the upper left corner of the image is placed 2cm to the right and 1cm below the upper left corner of the padding box. top Equivalent to '0%' for the vertical position. right Equivalent to '100%' for the horizontal position. bottom Equivalent to '100%' for the vertical position. left Equivalent to '0%' for the horizontal position. center Equivalent to '50%' for the horizontal position if it is not otherwise given, or '50%' for the vertical position if it is. However, the position is undefined in CSS 2.1 if the image has an intrinsic ratio, but no intrinsic size. Example(s): body { background: url("banner.jpeg") right top } /* 100% 0% */ body { background: url("banner.jpeg") top center } /* 50% 0% */ body { background: url("banner.jpeg") center } /* 50% 50% */ body { background: url("banner.jpeg") bottom } /* 50% 100% */ The tiling and positioning of the background-image on inline elements is undefined in this specification. A future level of CSS may define the tiling and positioning of the background-image on inline elements. If the background image is fixed within the viewport (see the 'background-attachment' property), the image is placed relative to the viewport instead of the element's padding box. For example, Example(s): body { background-image: url("logo.png"); background-attachment: fixed; background-position: 100% 100%; background-repeat: no-repeat; } In the example above, the (single) image is placed in the lower-right corner of the viewport. 'background' Value: [<'background-color'> || <'background-image'> || <'background-repeat'> || <'background-attachment'> || <'background-position'>] | inherit Initial: see individual properties Applies to: all elements Inherited: no Percentages: allowed on 'background-position' Media: visual Computed value: see individual properties The 'background' property is a shorthand property for setting the individual background properties (i.e., 'background-color', 'background-image', 'background-repeat', 'background-attachment' and 'background-position') at the same place in the style sheet. Given a valid declaration, the 'background' property first sets all the individual background properties to their initial values, then assigns explicit values given in the declaration. Example(s): In the first rule of the following example, only a value for 'background-color' has been given and the other individual properties are set to their initial value. In the second rule, all individual properties have been specified. BODY { background: red } P { background: url("chess.png") gray 50% repeat fixed } 15 Fonts Contents * 15.1 Introduction * 15.2 Font matching algorithm * 15.3 Font family: the 'font-family' property + 15.3.1 Generic font families o 15.3.1.1 serif o 15.3.1.2 sans-serif o 15.3.1.3 cursive o 15.3.1.4 fantasy o 15.3.1.5 monospace * 15.4 Font styling: the 'font-style' property * 15.5 Small-caps: the 'font-variant' property * 15.6 Font boldness: the 'font-weight' property * 15.7 Font size: the 'font-size' property * 15.8 Shorthand font property: the 'font' property 15.1 Introduction Setting font properties will be among the most common uses of style sheets. Unfortunately, there exists no well-defined and universally accepted taxonomy for classifying fonts, and terms that apply to one font family may not be appropriate for others. E.g., 'italic' is commonly used to label slanted text, but slanted text may also be labeled as being Oblique, Slanted, Incline, Cursive or Kursiv. Therefore it is not a simple problem to map typical font selection properties to a specific font. 15.2 Font matching algorithm Because there is no accepted, universal taxonomy of font properties, matching of properties to font faces must be done carefully. The properties are matched in a well-defined order to insure that the results of this matching process are as consistent as possible across UAs (assuming that the same library of font faces is presented to each of them). 1. The User Agent makes (or accesses) a database of relevant CSS 2.1 properties of all the fonts of which the UA is aware. If there are two fonts with exactly the same properties, the user agent selects one of them. 2. At a given element and for each character in that element, the UA assembles the font properties applicable to that element. Using the complete set of properties, the UA uses the 'font-family' property to choose a tentative font family. The remaining properties are tested against the family according to the matching criteria described with each property. If there are matches for all the remaining properties, then that is the matching font face for the given element or character. 3. If there is no matching font face within the 'font-family' being processed by step 2, and if there is a next alternative 'font-family' in the font set, then repeat step 2 with the next alternative 'font-family'. 4. If there is a matching font face, but it does not contain a glyph for the current character, and if there is a next alternative 'font-family' in the font sets, then repeat step 2 with the next alternative 'font-family'. 5. If there is no font within the family selected in 2, then use a UA-dependent default 'font-family' and repeat step 2, using the best match that can be obtained within the default font. If a particular character cannot be displayed using this font, then the UA may use other means to determine a suitable font for that character. The UA should map each character for which it has no suitable font to a visible symbol chosen by the UA, preferably a "missing character" glyph from one of the font faces available to the UA. (The above algorithm can be optimized to avoid having to revisit the CSS 2.1 properties for each character.) The per-property matching rules from (2) above are as follows: 1. 'font-style' is tried first. 'Italic' will be satisfied if there is either a face in the UA's font database labeled with the CSS keyword 'italic' (preferred) or 'oblique'. Otherwise the values must be matched exactly or font-style will fail. 2. 'font-variant' is tried next. 'Small-caps' matches (1) a font labeled as 'small-caps', (2) a font in which the small caps are synthesized, or (3) a font where all lowercase letters are replaced by upper case letters. A small-caps font may be synthesized by electronically scaling uppercase letters from a normal font. 'normal' matches a font's normal (non-small-caps) variant. A font cannot fail to have a normal variant. A font that is only available as small-caps shall be selectable as either a 'normal' face or a 'small-caps' face. 3. 'font-weight' is matched next, it will never fail. (See 'font-weight' below.) 4. 'font-size' must be matched within a UA-dependent margin of tolerance. (Typically, sizes for scalable fonts are rounded to the nearest whole pixel, while the tolerance for bitmapped fonts could be as large as 20%.) Further computations, e.g., by 'em' values in other properties, are based on the computed value of 'font-size'. 15.3 Font family: the 'font-family' property 'font-family' Value: [[ | ] [, | ]* ] | inherit Initial: depends on user agent Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified The property value is a prioritized list of font family names and/or generic family names. Unlike most other CSS properties, component values are separated by a comma to indicate that they are alternatives: body { font-family: Gill, Helvetica, sans-serif } Although many fonts provide the "missing character" glyph, typically an open box, as its name implies this should not be considered a match for characters that cannot be found in the font. (It should, however, be considered a match for U+FFFD, the "missing character" character's code point). There are two types of font family names: The name of a font family of choice. In the last example, "Gill" and "Helvetica" are font families. In the example above, the last value is a generic family name. The following generic families are defined: + 'serif' (e.g., Times) + 'sans-serif' (e.g., Helvetica) + 'cursive' (e.g., Zapf-Chancery) + 'fantasy' (e.g., Western) + 'monospace' (e.g., Courier) Style sheet designers are encouraged to offer a generic font family as a last alternative. Generic font family names are keywords and must NOT be quoted. Font family names must either be given quoted as strings, or unquoted as a sequence of one or more identifiers. This means most punctuation characters and digits at the start of each token must be escaped in unquoted font family names. For example, the following declarations are invalid: font-family: Red/Black, sans-serif; font-family: "Lucida" Grande, sans-serif; font-family: Ahem!, sans-serif; font-family: test@foo, sans-serif; font-family: #POUND, sans-serif; font-family: Hawaii 5-0, sans-serif; If a sequence of identifiers is given as a font family name, the computed value is the name converted to a string by joining all the identifiers in the sequence by single spaces. To avoid mistakes in escaping, it is recommended to quote font family names that contain white space, digits, or punctuation characters other than hyphens: body { font-family: "New Century Schoolbook", serif } Font family names that happen to be the same as a keyword value ('inherit', 'serif', 'sans-serif', 'monospace', 'fantasy', and 'cursive') must be quoted to prevent confusion with the keywords with the same names. The keywords 'initial' and 'default' are reserved for future use and must also be quoted when used as font names. UAs must not consider these keywords as matching the ' ' type. 15.3.1 Generic font families Generic font families are a fallback mechanism, a means of preserving some of the style sheet author's intent in the worst case when none of the specified fonts can be selected. For optimum typographic control, particular named fonts should be used in style sheets. All five generic font families are defined to exist in all CSS implementations (they need not necessarily map to five distinct actual fonts). User agents should provide reasonable default choices for the generic font families, which express the characteristics of each family as well as possible within the limits allowed by the underlying technology. User agents are encouraged to allow users to select alternative choices for the generic fonts. 15.3.1.1 serif Glyphs of serif fonts, as the term is used in CSS, tend to have finishing strokes, flared or tapering ends, or have actual serifed endings (including slab serifs). Serif fonts are typically proportionately-spaced. They often display a greater variation between thick and thin strokes than fonts from the 'sans-serif' generic font family. CSS uses the term 'serif' to apply to a font for any script, although other names may be more familiar for particular scripts, such as Mincho (Japanese), Sung or Song (Chinese), Totum or Kodig (Korean). Any font that is so described may be used to represent the generic 'serif' family. Examples of fonts that fit this description include: Latin fonts Times New Roman, Bodoni, Garamond, Minion Web, ITC Stone Serif, MS Georgia, Bitstream Cyberbit Greek fonts Bitstream Cyberbit Cyrillic fonts Adobe Minion Cyrillic, Excelsior Cyrillic Upright, Monotype Albion 70, Bitstream Cyberbit, ER Bukinist Hebrew fonts New Peninim, Raanana, Bitstream Cyberbit Japanese fonts Ryumin Light-KL, Kyokasho ICA, Futo Min A101 Arabic fonts Bitstream Cyberbit Cherokee fonts Lo Cicero Cherokee 15.3.1.2 sans-serif Glyphs in sans-serif fonts, as the term is used in CSS, tend to have stroke endings that are plain -- with little or no flaring, cross stroke, or other ornamentation. Sans-serif fonts are typically proportionately-spaced. They often have little variation between thick and thin strokes, compared to fonts from the 'serif' family. CSS uses the term 'sans-serif' to apply to a font for any script, although other names may be more familiar for particular scripts, such as Gothic (Japanese), Kai (Chinese), or Pathang (Korean). Any font that is so described may be used to represent the generic 'sans-serif' family. Examples of fonts that fit this description include: Latin fonts MS Trebuchet, ITC Avant Garde Gothic, MS Arial, MS Verdana, Univers, Futura, ITC Stone Sans, Gill Sans, Akzidenz Grotesk, Helvetica Greek fonts Attika, Typiko New Era, MS Tahoma, Monotype Gill Sans 571, Helvetica Greek Cyrillic fonts Helvetica Cyrillic, ER Univers, Lucida Sans Unicode, Bastion Hebrew fonts Arial Hebrew, MS Tahoma Japanese fonts Shin Go, Heisei Kaku Gothic W5 Arabic fonts MS Tahoma 15.3.1.3 cursive Glyphs in cursive fonts, as the term is used in CSS, generally have either joining strokes or other cursive characteristics beyond those of italic typefaces. The glyphs are partially or completely connected, and the result looks more like handwritten pen or brush writing than printed letterwork. Fonts for some scripts, such as Arabic, are almost always cursive. CSS uses the term 'cursive' to apply to a font for any script, although other names such as Chancery, Brush, Swing and Script are also used in font names. Examples of fonts that fit this description include: Latin fonts Caflisch Script, Adobe Poetica, Sanvito, Ex Ponto, Snell Roundhand, Zapf-Chancery Cyrillic fonts ER Architekt Hebrew fonts Corsiva Arabic fonts DecoType Naskh, Monotype Urdu 507 15.3.1.4 fantasy Fantasy fonts, as used in CSS, are primarily decorative while still containing representations of characters (as opposed to Pi or Picture fonts, which do not represent characters). Examples include: Latin fonts Alpha Geometrique, Critter, Cottonwood, FB Reactor, Studz 15.3.1.5 monospace The sole criterion of a monospace font is that all glyphs have the same fixed width. (This can make some scripts, such as Arabic, look most peculiar.) The effect is similar to a manual typewriter, and is often used to set samples of computer code. Examples of fonts which fit this description include: Latin fonts Courier, MS Courier New, Prestige, Everson Mono Greek Fonts MS Courier New, Everson Mono Cyrillic fonts ER Kurier, Everson Mono Japanese fonts Osaka Monospaced Cherokee fonts Everson Mono 15.4 Font styling: the 'font-style' property 'font-style' Value: normal | italic | oblique | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified The 'font-style' property selects between normal (sometimes referred to as "roman" or "upright"), italic and oblique faces within a font family. A value of 'normal' selects a font that is classified as 'normal' in the UA's font database, while 'oblique' selects a font that is labeled 'oblique'. A value of 'italic' selects a font that is labeled 'italic', or, if that is not available, one labeled 'oblique'. The font that is labeled 'oblique' in the UA's font database may actually have been generated by electronically slanting a normal font. Fonts with Oblique, Slanted or Incline in their names will typically be labeled 'oblique' in the UA's font database. Fonts with Italic, Cursive or Kursiv in their names will typically be labeled 'italic'. h1, h2, h3 { font-style: italic } h1 em { font-style: normal } In the example above, emphasized text within 'H1' will appear in a normal face. 15.5 Small-caps: the 'font-variant' property 'font-variant' Value: normal | small-caps | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified Another type of variation within a font family is the small-caps. In a small-caps font the lower case letters look similar to the uppercase ones, but in a smaller size and with slightly different proportions. The 'font-variant' property selects that font. A value of 'normal' selects a font that is not a small-caps font, 'small-caps' selects a small-caps font. It is acceptable (but not required) in CSS 2.1 if the small-caps font is a created by taking a normal font and replacing the lower case letters by scaled uppercase characters. As a last resort, uppercase letters will be used as replacement for a small-caps font. The following example results in an 'H3' element in small-caps, with any emphasized words in oblique, and any emphasized words within an 'H3' oblique small-caps: h3 { font-variant: small-caps } em { font-style: oblique } There may be other variants in the font family as well, such as fonts with old-style numerals, small-caps numerals, condensed or expanded letters, etc. CSS 2.1 has no properties that select those. Note: insofar as this property causes text to be transformed to uppercase, the same considerations as for 'text-transform' apply. 15.6 Font boldness: the 'font-weight' property 'font-weight' Value: normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: see text The 'font-weight' property selects the weight of the font. The values '100' to '900' form an ordered sequence, where each number indicates a weight that is at least as dark as its predecessor. The keyword 'normal' is synonymous with '400', and 'bold' is synonymous with '700'. Keywords other than 'normal' and 'bold' have been shown to be often confused with font names and a numerical scale was therefore chosen for the 9-value list. p { font-weight: normal } /* 400 */ h1 { font-weight: 700 } /* bold */ The 'bolder' and 'lighter' values select font weights that are relative to the weight inherited from the parent: strong { font-weight: bolder } Fonts (the font data) typically have one or more properties whose values are names that are descriptive of the "weight" of a font. There is no accepted, universal meaning to these weight names. Their primary role is to distinguish faces of differing darkness within a single font family. Usage across font families is quite variant; for example, a font that one might think of as being bold might be described as being Regular, Roman, Book, Medium, Semi- or DemiBold, Bold, or Black, depending on how black the "normal" face of the font is within the design. Because there is no standard usage of names, the weight property values in CSS 2.1 are given on a numerical scale in which the value '400' (or 'normal') corresponds to the "normal" text face for that family. The weight name associated with that face will typically be Book, Regular, Roman, Normal or sometimes Medium. The association of other weights within a family to the numerical weight values is intended only to preserve the ordering of darkness within that family. However, the following heuristics tell how the assignment is done in this case: * If the font family already uses a numerical scale with nine values (like e.g., OpenType does), the font weights should be mapped directly. * If there is both a face labeled Medium and one labeled Book, Regular, Roman or Normal, then the Medium is normally assigned to the '500'. * The font labeled "Bold" will often correspond to the weight value '700'. Once the font family's weights are mapped onto the CSS scale, missing weights are selected as follows: * If the desired weight is less than 400, weights below the desired weight are checked in descending order followed by weights above the desired weight in ascending order until a match is found. * If the desired weight is greater than 500, weights above desired weight are checked in ascending order followed by weights below the desired weight in descending order until a match is found. * If the desired weight is 400, 500 is checked first and then the rule for desired weights less than 400 is used. * If the desired weight is 500, 400 is checked first and then the rule for desired weights less than 400 is used. The following two examples show typical mappings. Assume four weights in the "Rattlesnake" family, from lightest to darkest: Regular, Medium, Bold, Heavy. CAPTION: First example of font-weight mapping Available faces Assignments Filling the holes "Rattlesnake Regular" 400 100, 200, 300 "Rattlesnake Medium" 500 "Rattlesnake Bold" 700 600 "Rattlesnake Heavy" 800 900 Assume six weights in the "Ice Prawn" family: Book, Medium, Bold, Heavy, Black, ExtraBlack. Note that in this instance the user agent has decided not to assign a numeric value to "Ice Prawn ExtraBlack". CAPTION: Second example of font-weight mapping Available faces Assignments Filling the holes "Ice Prawn Book" 400 100, 200, 300 "Ice Prawn Medium" 500 "Ice Prawn Bold" 700 600 "Ice Prawn Heavy" 800 "Ice Prawn Black" 900 "Ice Prawn ExtraBlack" (none) Values of 'bolder' and 'lighter' indicate values relative to the weight of the parent element. Based on the inherited weight value, the weight used is calculated using the chart below. Child elements inherit the calculated weight, not a value of 'bolder' or 'lighter'. CAPTION: The meaning of 'bolder' and 'lighter' Inherited value bolder lighter 100 400 100 200 400 100 300 400 100 400 700 100 500 700 100 600 900 400 700 900 400 800 900 700 900 900 700 The table above is equivalent to selecting the next relative bolder or lighter face, given a font family containing normal and bold faces along with a thin and a heavy face. Authors who desire finer control over the exact weight values used for a given element should use numerical values instead of relative weights. There is no guarantee that there will be a darker face for each of the 'font-weight' values; for example, some fonts may have only a normal and a bold face, while others may have eight face weights. There is no guarantee on how a UA will map font faces within a family to weight values. The only guarantee is that a face of a given value will be no less dark than the faces of lighter values. 15.7 Font size: the 'font-size' property 'font-size' Value: | | | | inherit Initial: medium Applies to: all elements Inherited: yes Percentages: refer to inherited font size Media: visual Computed value: absolute length The font size corresponds to the em square, a concept used in typography. Note that certain glyphs may bleed outside their em squares. Values have the following meanings: An keyword is an index to a table of font sizes computed and kept by the UA. Possible values are: [ xx-small | x-small | small | medium | large | x-large | xx-large ] The following table provides user agent guidelines for the absolute-size mapping to HTML heading and absolute font-sizes. The 'medium' value is the user's preferred font size and is used as the reference middle value. CSS absolute-size values xx-small x-small small medium large x-large xx-large HTML font sizes 1 2 3 4 5 6 7 Implementors should build a table of scaling factors for absolute-size keywords relative to the 'medium' font size and the particular device and its characteristics (e.g., the resolution of the device). Different media may need different scaling factors. Also, the UA should take the quality and availability of fonts into account when computing the table. The table may be different from one font family to another. Note 1. To preserve readability, a UA applying these guidelines should nevertheless avoid creating font-size resulting in less than 9 pixels per EM unit on a computer display. Note 2. In CSS1, the suggested scaling factor between adjacent indexes was 1.5, which user experience proved to be too large. In CSS2, the suggested scaling factor for a computer screen between adjacent indexes was 1.2, which still created issues for the small sizes. Implementation experience has demonstrated that a fixed ratio between adjacent absolute-size keywords is problematic, and this specification does not recommend such a fixed ratio. A keyword is interpreted relative to the table of font sizes and the font size of the parent element. Possible values are: [ larger | smaller ]. For example, if the parent element has a font size of 'medium', a value of 'larger' will make the font size of the current element be 'large'. If the parent element's size is not close to a table entry, the UA is free to interpolate between table entries or round off to the closest one. The UA may have to extrapolate table values if the numerical value goes beyond the keywords. Length and percentage values should not take the font size table into account when calculating the font size of the element. Negative values are not allowed. On all other properties, 'em' and 'ex' length values refer to the computed font size of the current element. On the 'font-size' property, these length units refer to the computed font size of the parent element. Note that an application may reinterpret an explicit size, depending on the context. E.g., inside a VR scene a font may get a different size because of perspective distortion. Examples: p { font-size: 16px; } @media print { p { font-size: 12pt; } } blockquote { font-size: larger } em { font-size: 150% } em { font-size: 1.5em } 15.8 Shorthand font property: the 'font' property 'font' Value: [ [ <'font-style'> || <'font-variant'> || <'font-weight'> ]? <'font-size'> [ / <'line-height'> ]? <'font-family'> ] | caption | icon | menu | message-box | small-caption | status-bar | inherit Initial: see individual properties Applies to: all elements Inherited: yes Percentages: see individual properties Media: visual Computed value: see individual properties The 'font' property is, except as described below, a shorthand property for setting 'font-style', 'font-variant', 'font-weight', 'font-size', 'line-height' and 'font-family' at the same place in the style sheet. The syntax of this property is based on a traditional typographical shorthand notation to set multiple properties related to fonts. All font-related properties are first reset to their initial values, including those listed in the preceding paragraph. Then, those properties that are given explicit values in the 'font' shorthand are set to those values. For a definition of allowed and initial values, see the previously defined properties. p { font: 12px/14px sans-serif } p { font: 80% sans-serif } p { font: x-large/110% "New Century Schoolbook", serif } p { font: bold italic large Palatino, serif } p { font: normal small-caps 120%/120% fantasy } In the second rule, the font size percentage value ('80%') refers to the font size of the parent element. In the third rule, the line height percentage refers to the font size of the element itself. In the first three rules above, the 'font-style', 'font-variant' and 'font-weight' are not explicitly mentioned, which means they are all three set to their initial value ('normal'). The fourth rule sets the 'font-weight' to 'bold', the 'font-style' to 'italic' and implicitly sets 'font-variant' to 'normal'. The fifth rule sets the 'font-variant' ('small-caps'), the 'font-size' (120% of the parent's font), the 'line-height' (120% times the font size) and the 'font-family' ('fantasy'). It follows that the keyword 'normal' applies to the two remaining properties: 'font-style' and 'font-weight'. The following values refer to system fonts: caption The font used for captioned controls (e.g., buttons, drop-downs, etc.). icon The font used to label icons. menu The font used in menus (e.g., dropdown menus and menu lists). message-box The font used in dialog boxes. small-caption The font used for labeling small controls. status-bar The font used in window status bars. System fonts may only be set as a whole; that is, the font family, size, weight, style, etc. are all set at the same time. These values may then be altered individually if desired. If no font with the indicated characteristics exists on a given platform, the user agent should either intelligently substitute (e.g., a smaller version of the 'caption' font might be used for the 'small-caption' font), or substitute a user agent default font. As for regular fonts, if, for a system font, any of the individual properties are not part of the operating system's available user preferences, those properties should be set to their initial values. That is why this property is "almost" a shorthand property: system fonts can only be specified with this property, not with 'font-family' itself, so 'font' allows authors to do more than the sum of its subproperties. However, the individual properties such as 'font-weight' are still given values taken from the system font, which can be independently varied. Example(s): button { font: 300 italic 1.3em/1.7em "FB Armada", sans-serif } button p { font: menu } button p em { font-weight: bolder } If the font used for dropdown menus on a particular system happened to be, for example, 9-point Charcoal, with a weight of 600, then P elements that were descendants of BUTTON would be displayed as if this rule were in effect: button p { font: 600 9px Charcoal } Because the 'font' shorthand property resets any property not explicitly given a value to its initial value, this has the same effect as this declaration: button p { font-family: Charcoal; font-style: normal; font-variant: normal; font-weight: 600; font-size: 9px; line-height: normal; } 16 Text Contents * 16.1 Indentation: the 'text-indent' property * 16.2 Alignment: the 'text-align' property * 16.3 Decoration + 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property * 16.4 Letter and word spacing: the 'letter-spacing' and 'word-spacing' properties * 16.5 Capitalization: the 'text-transform' property * 16.6 White space: the 'white-space' property + 16.6.1 The 'white-space' processing model + 16.6.2 Example of bidirectionality with white space collapsing + 16.6.3 Control and combining characters' details The properties defined in the following sections affect the visual presentation of characters, spaces, words, and paragraphs. 16.1 Indentation: the 'text-indent' property 'text-indent' Value: | | inherit Initial: 0 Applies to: block containers Inherited: yes Percentages: refer to width of containing block Media: visual Computed value: the percentage as specified or the absolute length This property specifies the indentation of the first line of text in a block container. More precisely, it specifies the indentation of the first box that flows into the block's first line box. The box is indented with respect to the left (or right, for right-to-left layout) edge of the line box. User agents must render this indentation as blank space. 'Text-indent' only affects a line if it is the first formatted line of an element. For example, the first line of an anonymous block box is only affected if it is the first child of its parent element. Values have the following meanings: The indentation is a fixed length. The indentation is a percentage of the containing block width. The value of 'text-indent' may be negative, but there may be implementation-specific limits. If the value of 'text-indent' is either negative or exceeds the width of the block, that first box, described above, can overflow the block. The value of 'overflow' will affect whether such text that overflows the block is visible. Example(s): The following example causes a '3em' text indent. p { text-indent: 3em } Note: Since the 'text-indent' property inherits, when specified on a block element, it will affect descendant inline-block elements. For this reason, it is often wise to specify 'text-indent: 0' on elements that are specified 'display:inline-block'. 16.2 Alignment: the 'text-align' property 'text-align' Value: left | right | center | justify | inherit Initial: a nameless value that acts as 'left' if 'direction' is 'ltr', 'right' if 'direction' is 'rtl' Applies to: block containers Inherited: yes Percentages: N/A Media: visual Computed value: the initial value or as specified This property describes how inline-level content of a block container is aligned. Values have the following meanings: left, right, center, justify Left, right, center, and justify text, respectively, as described in the section on inline formatting. A block of text is a stack of line boxes. In the case of 'left', 'right' and 'center', this property specifies how the inline-level boxes within each line box align with respect to the line box's left and right sides; alignment is not with respect to the viewport. In the case of 'justify', this property specifies that the inline-level boxes are to be made flush with both sides of the line box if possible, by expanding or contracting the contents of inline boxes, else aligned as for the initial value. (See also 'letter-spacing' and 'word-spacing'.) If an element has a computed value for 'white-space' of 'pre' or 'pre-wrap', then neither the glyphs of that element's text content nor its white space may be altered for the purpose of justification. Note: CSS may add a way to justify text with 'white-space: pre-wrap' in the future. Example(s): In this example, note that since 'text-align' is inherited, all block-level elements inside DIV elements with a class name of 'important' will have their inline content centered. div.important { text-align: center } Note. The actual justification algorithm used depends on the user-agent and the language/script of the text. Conforming user agents may interpret the value 'justify' as 'left' or 'right', depending on whether the element's default writing direction is left-to-right or right-to-left, respectively. 16.3 Decoration 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property 'text-decoration' Value: none | [ underline || overline || line-through || blink ] | inherit Initial: none Applies to: all elements Inherited: no (see prose) Percentages: N/A Media: visual Computed value: as specified This property describes decorations that are added to the text of an element using the element's color. When specified on or propagated to an inline element, it affects all the boxes generated by that element, and is further propagated to any in-flow block-level boxes that split the inline (see section 9.2.1.1). But, in CSS 2.1, it is undefined whether the decoration propagates into block-level tables. For block containers that establish an inline formatting context, the decorations are propagated to an anonymous inline element that wraps all the in-flow inline-level children of the block container. For all other elements it is propagated to any in-flow children. Note that text decorations are not propagated to floating and absolutely positioned descendants, nor to the contents of atomic inline-level descendants such as inline blocks and inline tables. Underlines, overlines, and line-throughs are applied only to text (including white space, letter spacing, and word spacing): margins, borders, and padding are skipped. User agents must not render these text decorations on content that is not text. For example, images and inline blocks must not be underlined. Note. If an element E has both 'visibility: hidden' and 'text-decoration: underline', the underline is invisible (although any decoration of E's parent is visible.) However, CSS 2.1 does not specify if the underline is visible or invisible in E's children: underlined or not? This is expected to be specified in level 3 of CSS. The 'text-decoration' property on descendant elements cannot have any effect on the decoration of the ancestor. In determining the position of and thickness of text decoration lines, user agents may consider the font sizes of and dominant baselines of descendants, but must use the same baseline and thickness on each line. Relatively positioning a descendant moves all text decorations affecting it along with the descendant's text; it does not affect calculation of the decoration's initial position on that line. Values have the following meanings: none Produces no text decoration. underline Each line of text is underlined. overline Each line of text has a line above it. line-through Each line of text has a line through the middle. blink Text blinks (alternates between visible and invisible). Conforming user agents may simply not blink the text. Note that not blinking the text is one technique to satisfy checkpoint 3.3 of WAI-UAAG. The color(s) required for the text decoration must be derived from the 'color' property value of the element on which 'text-decoration' is set. The color of decorations must remain the same even if descendant elements have different 'color' values. Some user agents have implemented text-decoration by propagating the decoration to the descendant elements as opposed to preserving a constant thickness and line position as described above. This was arguably allowed by the looser wording in CSS2. SVG1, CSS1-only, and CSS2-only user agents may implement the older model and still claim conformance to this part of CSS 2.1. (This does not apply to UAs developed after this specification was released.) Example(s): In the following example for HTML, the text content of all A elements acting as hyperlinks (whether visited or not) will be underlined: a:visited,a:link { text-decoration: underline } Example(s): In the following style sheet and document fragment: blockquote { text-decoration: underline; color: blue; } em { display: block; } cite { color: fuchsia; }
...the underlining for the blockquote element is propagated to an anonymous inline element that surrounds the span element, causing the text "Help, help!" to be blue, with the blue underlining from the anonymous inline underneath it, the color being taken from the blockquote element. The text in the em block is also underlined, as it is in an in-flow block to which the underline is propagated. The final line of text is fuchsia, but the underline underneath it is still the blue underline from the anonymous inline element. Sample rendering of the above underline example This diagram shows the boxes involved in the example above. The rounded aqua line represents the anonymous inline element wrapping the inline contents of the paragraph element, the rounded blue line represents the span element, and the orange lines represent the blocks. 16.4 Letter and word spacing: the 'letter-spacing' and 'word-spacing' properties 'letter-spacing' Value: normal | | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: 'normal' or absolute length This property specifies spacing behavior between text characters. Values have the following meanings: normal The spacing is the normal spacing for the current font. This value allows the user agent to alter the space between characters in order to justify text. This value indicates inter-character space in addition to the default space between characters. Values may be negative, but there may be implementation-specific limits. User agents may not further increase or decrease the inter-character space in order to justify text. Character spacing algorithms are user agent-dependent. Example(s): In this example, the space between characters in BLOCKQUOTE elements is increased by '0.1em'. blockquote { letter-spacing: 0.1em } In the following example, the user agent is not permitted to alter inter-character space: blockquote { letter-spacing: 0cm } /* Same as '0' */ When the resultant space between two characters is not the same as the default space, user agents should not use ligatures. 'word-spacing' Value: normal | | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: for 'normal' the value '0'; otherwise the absolute length This property specifies spacing behavior between words. Values have the following meanings: normal The normal inter-word space, as defined by the current font and/or the UA. This value indicates inter-word space in addition to the default space between words. Values may be negative, but there may be implementation-specific limits. Word spacing algorithms are user agent-dependent. Word spacing is also influenced by justification (see the 'text-align' property). Word spacing affects each space (U+0020) and non-breaking space (U+00A0), left in the text after the white space processing rules have been applied. The effect of the property on other word-separator characters is undefined. However general punctuation, characters with zero advance width (such as the zero with space U+200B) and fixed-width spaces (such as U+3000 and U+2000 through U+200A) are not affected. Example(s): In this example, the word-spacing between each word in H1 elements is increased by '1em'. h1 { word-spacing: 1em } 16.5 Capitalization: the 'text-transform' property 'text-transform' Value: capitalize | uppercase | lowercase | none | inherit Initial: none Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified This property controls capitalization effects of an element's text. Values have the following meanings: capitalize Puts the first character of each word in uppercase; other characters are unaffected. uppercase Puts all characters of each word in uppercase. lowercase Puts all characters of each word in lowercase. none No capitalization effects. The actual transformation in each case is written language dependent. See BCP 47 ([BCP47]) for ways to find the language of an element. Only characters belonging to "bicameral scripts" [UNICODE] are affected. Example(s): In this example, all text in an H1 element is transformed to uppercase text. h1 { text-transform: uppercase } 16.6 White space: the 'white-space' property 'white-space' Value: normal | pre | nowrap | pre-wrap | pre-line | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified This property declares how white space inside the element is handled. Values have the following meanings: normal This value directs user agents to collapse sequences of white space, and break lines as necessary to fill line boxes. pre This value prevents user agents from collapsing sequences of white space. Lines are only broken at preserved newline characters. nowrap This value collapses white space as for 'normal', but suppresses line breaks within text. pre-wrap This value prevents user agents from collapsing sequences of white space. Lines are broken at preserved newline characters, and as necessary to fill line boxes. pre-line This value directs user agents to collapse sequences of white space. Lines are broken at preserved newline characters, and as necessary to fill line boxes. Newlines in the source can be represented by a carriage return (U+000D), a linefeed (U+000A) or both (U+000D U+000A) or by some other mechanism that identifies the beginning and end of document segments, such as the SGML RECORD-START and RECORD-END tokens. The CSS 'white-space' processing model assumes all newlines have been normalized to line feeds. UAs that recognize other newline representations must apply the white space processing rules as if this normalization has taken place. If no newline rules are specified for the document language, each carriage return (U+000D) and CRLF sequence (U+000D U+000A) in the document text is treated as single line feed character. This default normalization rule also applies to generated content. UAs must recognize line feeds (U+000A) as newline characters. UAs may additionally treat other forced break characters as newline characters per UAX14. Example(s): The following examples show what white space behavior is expected from the PRE and P elements and the "nowrap" attribute in HTML. pre { white-space: pre } p { white-space: normal } td[nowrap] { white-space: nowrap } In addition, the effect of an HTML PRE element with the non-standard "wrap" attribute is demonstrated by the following example: pre[wrap] { white-space: pre-wrap } 16.6.1 The 'white-space' processing model For each inline element (including anonymous inline elements), the following steps are performed, treating bidi formatting characters as if they were not there: 1. Each tab (U+0009), carriage return (U+000D), or space (U+0020) character surrounding a linefeed (U+000A) character is removed if 'white-space' is set to 'normal', 'nowrap', or 'pre-line'. 2. If 'white-space' is set to 'pre' or 'pre-wrap', any sequence of spaces (U+0020) unbroken by an element boundary is treated as a sequence of non-breaking spaces. However, for 'pre-wrap', a line breaking opportunity exists at the end of the sequence. 3. If 'white-space' is set to 'normal' or 'nowrap', linefeed characters are transformed for rendering purpose into one of the following characters: a space character, a zero width space character (U+200B), or no character (i.e., not rendered), according to UA-specific algorithms based on the content script. 4. If 'white-space' is set to 'normal', 'nowrap', or 'pre-line', 1. every tab (U+0009) is converted to a space (U+0020) 2. any space (U+0020) following another space (U+0020) â even a space before the inline, if that space also has 'white-space' set to 'normal', 'nowrap' or 'pre-line' â is removed. Then, the block container's inlines are laid out. Inlines are laid out, taking bidi reordering into account, and wrapping as specified by the 'white-space' property. When wrapping, line breaking opportunities are determined based on the text prior to the white space collapsing steps above. As each line is laid out, 1. If a space (U+0020) at the beginning of a line has 'white-space' set to 'normal', 'nowrap', or 'pre-line', it is removed. 2. All tabs (U+0009) are rendered as a horizontal shift that lines up the start edge of the next glyph with the next tab stop. Tab stops occur at points that are multiples of 8 times the width of a space (U+0020) rendered in the block's font from the block's starting content edge. 3. If a space (U+0020) at the end of a line has 'white-space' set to 'normal', 'nowrap', or 'pre-line', it is also removed. 4. If spaces (U+0020) or tabs (U+0009) at the end of a line have 'white-space' set to 'pre-wrap', UAs may visually collapse them. Floated and absolutely-positioned elements do not introduce a line breaking opportunity. Note. CSS 2.1 does not fully define where line breaking opportunities occur. 16.6.2 Example of bidirectionality with white space collapsing Given the following markup fragment, taking special note of spaces (with varied backgrounds and borders for emphasis and identification): A B C ...where the element represents a left-to-right embedding and the element represents a right-to-left embedding, and assuming that the 'white-space' property is set to 'normal', the above processing model would result in the following: * The space before the B ( ) would collapse with the space after the A ( ). * The space before the C ( ) would collapse with the space after the B ( ). This would leave two spaces, one after the A in the left-to-right embedding level, and one after the B in the right-to-left embedding level. This is then rendered according to the Unicode bidirectional algorithm, with the end result being: A BC Note that there are two spaces between A and B, and none between B and C. This can sometimes be avoided by using the natural bidirectionality of characters instead of explicit embedding levels. Also, it is good to avoid spaces immediately inside start and end tags, as these tend to do weird things when dealing with white space collapsing. 16.6.3 Control and combining characters' details Control characters other than U+0009 (tab), U+000A (line feed), U+0020 (space), and U+202x (bidi formatting characters) are treated as characters to render in the same way as any normal character. Combining characters should be treated as part of the character with which they are supposed to combine. For example, :first-letter styles the entire glyph if you have content like "o ̈"; it does not just match the base character. 17 Tables Contents * 17.1 Introduction to tables * 17.2 The CSS table model + 17.2.1 Anonymous table objects * 17.3 Columns * 17.4 Tables in the visual formatting model + 17.4.1 Caption position and alignment * 17.5 Visual layout of table contents + 17.5.1 Table layers and transparency + 17.5.2 Table width algorithms: the 'table-layout' property o 17.5.2.1 Fixed table layout o 17.5.2.2 Automatic table layout + 17.5.3 Table height algorithms + 17.5.4 Horizontal alignment in a column + 17.5.5 Dynamic row and column effects * 17.6 Borders + 17.6.1 The separated borders model o 17.6.1.1 Borders and Backgrounds around empty cells: the 'empty-cells' property + 17.6.2 The collapsing border model o 17.6.2.1 Border conflict resolution + 17.6.3 Border styles 17.1 Introduction to tables This chapter defines the processing model for tables in CSS. Part of this processing model is the layout. For the layout, this chapter introduces two algorithms; the first, the fixed table layout algorithm, is well-defined, but the second, the automatic table layout algorithm, is not fully defined by this specification. For the automatic table layout algorithm, some widely deployed implementations have achieved relatively close interoperability. Table layout can be used to represent tabular relationships between data. Authors specify these relationships in the document language and can specify their presentation using CSS 2.1. In a visual medium, CSS tables can also be used to achieve specific layouts. In this case, authors should not use table-related elements in the document language, but should apply the CSS to the relevant structural elements to achieve the desired layout. Authors may specify the visual formatting of a table as a rectangular grid of cells. Rows and columns of cells may be organized into row groups and column groups. Rows, columns, row groups, column groups, and cells may have borders drawn around them (there are two border models in CSS 2.1). Authors may align data vertically or horizontally within a cell and align data in all cells of a row or column. Example(s): Here is a simple three-row, three-column table described in HTML 4: This is a simple 3x3 table Header 1 Cell 1 Cell 2 Header 2 Cell 3 Cell 4 Header 3 Cell 5 Cell 6 This code creates one table (the TABLE element), three rows (the TR elements), three header cells (the TH elements), and six data cells (the TD elements). Note that the three columns of this example are specified implicitly: there are as many columns in the table as required by header and data cells. The following CSS rule centers the text horizontally in the header cells and presents the text in the header cells with a bold font weight: th { text-align: center; font-weight: bold } The next rules align the text of the header cells on their baseline and vertically center the text in each data cell: th { vertical-align: baseline } td { vertical-align: middle } The next rules specify that the top row will be surrounded by a 3px solid blue border and each of the other rows will be surrounded by a 1px solid black border: table { border-collapse: collapse } tr#row1 { border: 3px solid blue } tr#row2 { border: 1px solid black } tr#row3 { border: 1px solid black } Note, however, that the borders around the rows overlap where the rows meet. What color (black or blue) and thickness (1px or 3px) will the border between row1 and row2 be? We discuss this in the section on border conflict resolution. The following rule puts the table caption above the table: caption { caption-side: top } The preceding example shows how CSS works with HTML 4 elements; in HTML 4, the semantics of the various table elements (TABLE, CAPTION, THEAD, TBODY, TFOOT, COL, COLGROUP, TH, and TD) are well-defined. In other document languages (such as XML applications), there may not be pre-defined table elements. Therefore, CSS 2.1 allows authors to "map" document language elements to table elements via the 'display' property. For example, the following rule makes the FOO element act like an HTML TABLE element and the BAR element act like a CAPTION element: FOO { display : table } BAR { display : table-caption } We discuss the various table elements in the following section. In this specification, the term table element refers to any element involved in the creation of a table. An internal table element is one that produces a row, row group, column, column group, or cell. 17.2 The CSS table model The CSS table model is based on the HTML4 table model, in which the structure of a table closely parallels the visual layout of the table. In this model, a table consists of an optional caption and any number of rows of cells. The table model is said to be "row primary" since authors specify rows, not columns, explicitly in the document language. Columns are derived once all the rows have been specified -- the first cell of each row belongs to the first column, the second to the second column, etc.). Rows and columns may be grouped structurally and this grouping reflected in presentation (e.g., a border may be drawn around a group of rows). Thus, the table model consists of tables, captions, rows, row groups (including header groups and footer groups), columns, column groups, and cells. The CSS model does not require that the document language include elements that correspond to each of these components. For document languages (such as XML applications) that do not have pre-defined table elements, authors must map document language elements to table elements; this is done with the 'display' property. The following 'display' values assign table formatting rules to an arbitrary element: table (In HTML: TABLE) Specifies that an element defines a block-level table: it is a rectangular block that participates in a block formatting context. inline-table (In HTML: TABLE) Specifies that an element defines an inline-level table: it is a rectangular block that participates in an inline formatting context). table-row (In HTML: TR) Specifies that an element is a row of cells. table-row-group (In HTML: TBODY) Specifies that an element groups one or more rows. table-header-group (In HTML: THEAD) Like 'table-row-group', but for visual formatting, the row group is always displayed before all other rows and row groups and after any top captions. Print user agents may repeat header rows on each page spanned by a table. If a table contains multiple elements with 'display: table-header-group', only the first is rendered as a header; the others are treated as if they had 'display: table-row-group'. table-footer-group (In HTML: TFOOT) Like 'table-row-group', but for visual formatting, the row group is always displayed after all other rows and row groups and before any bottom captions. Print user agents may repeat footer rows on each page spanned by a table. If a table contains multiple elements with 'display: table-footer-group', only the first is rendered as a footer; the others are treated as if they had 'display: table-row-group'. table-column (In HTML: COL) Specifies that an element describes a column of cells. table-column-group (In HTML: COLGROUP) Specifies that an element groups one or more columns. table-cell (In HTML: TD, TH) Specifies that an element represents a table cell. table-caption (In HTML: CAPTION) Specifies a caption for the table. All elements with 'display: table-caption' must be rendered, as described in section 17.4. Replaced elements with these 'display' values are treated as their given display types during layout. For example, an image that is set to 'display: table-cell' will fill the available cell space, and its dimensions might contribute towards the table sizing algorithms, as with an ordinary cell. Elements with 'display' set to 'table-column' or 'table-column-group' are not rendered (exactly as if they had 'display: none'), but they are useful, because they may have attributes which induce a certain style for the columns they represent. The default style sheet for HTML4 in the appendix illustrates the use of these values for HTML4: table { display: table } tr { display: table-row } thead { display: table-header-group } tbody { display: table-row-group } tfoot { display: table-footer-group } col { display: table-column } colgroup { display: table-column-group } td, th { display: table-cell } caption { display: table-caption } User agents may ignore these 'display' property values for HTML table elements, since HTML tables may be rendered using other algorithms intended for backwards compatible rendering. However, this is not meant to discourage the use of 'display: table' on other, non-table elements in HTML. 17.2.1 Anonymous table objects Document languages other than HTML may not contain all the elements in the CSS 2.1 table model. In these cases, the "missing" elements must be assumed in order for the table model to work. Any table element will automatically generate necessary anonymous table objects around itself, consisting of at least three nested objects corresponding to a 'table'/'inline-table' element, a 'table-row' element, and a 'table-cell' element. Missing elements generate anonymous objects (e.g., anonymous boxes in visual table layout) according to the following rules: For the purposes of these rules, the following terms are defined: row group box A 'table-row-group', 'table-header-group', or 'table-footer-group' proper table child A 'table-row' box, row group box, 'table-column' box, 'table-column-group' box, or 'table-caption' box. proper table row parent A 'table' or 'inline-table' box or row group box internal table box A 'table-cell' box, 'table-row' box, row group box, 'table-column' box, or 'table-column-group' box. tabular container A 'table-row' box or proper table row parent consecutive Two sibling boxes are consecutive if they have no intervening siblings other than, optionally, an anonymous inline containing only white spaces. A sequence of sibling boxes is consecutive if each box in the sequence is consecutive to the one before it in the sequence. For the purposes of these rules, out-of-flow elements are represented as inline elements of zero width and height. Their containing blocks are chosen accordingly. The following steps are performed in three stages. 1. Remove irrelevant boxes: 1. All child boxes of a 'table-column' parent are treated as if they had 'display: none'. 2. If a child C of a 'table-column-group' parent is not a 'table-column' box, then it is treated as if it had 'display: none'. 3. If a child C of a tabular container P is an anonymous inline box that contains only white space, and its immediately preceding and following siblings, if any, are proper table descendants of P and are either 'table-caption' or internal table boxes, then it is treated as if it had 'display: none'. A box D is a proper table descendant of A if D can be a descendant of A without causing the generation of any intervening 'table' or 'inline-table' boxes. 4. If a box B is an anonymous inline containing only white space, and is between two immediate siblings each of which is either an internal table box or a 'table-caption' box then B is treated as if it had 'display: none'. 2. Generate missing child wrappers: 1. If a child C of a 'table' or 'inline-table' box is not a proper table child, then generate an anonymous 'table-row' box around C and all consecutive siblings of C that are not proper table children. 2. If a child C of a row group box is not a 'table-row' box, then generate an anonymous 'table-row' box around C and all consecutive siblings of C that are not 'table-row' boxes. 3. If a child C of a 'table-row' box is not a 'table-cell', then generate an anonymous 'table-cell' box around C and all consecutive siblings of C that are not 'table-cell' boxes. 3. Generate missing parents: 1. For each 'table-cell' box C in a sequence of consecutive internal table and 'table-caption' siblings, if C's parent is not a 'table-row' then generate an anonymous 'table-row' box around C and all consecutive siblings of C that are 'table-cell' boxes. 2. For each proper table child C in a sequence of consecutive proper table children, if C is misparented then generate an anonymous 'table' or 'inline-table' box T around C and all consecutive siblings of C that are proper table children. (If C's parent is an 'inline' box, then T must be an 'inline-table' box; otherwise it must be a 'table' box.) o A 'table-row' is misparented if its parent is neither a row group box nor a 'table' or 'inline-table' box. o A 'table-column' box is misparented if its parent is neither a 'table-column-group' box nor a 'table' or 'inline-table' box. o A row group box, 'table-column-group' box, or 'table-caption' box is misparented if its parent is neither a 'table' box nor an 'inline-table' box. Example(s): In this XML example, a 'table' element is assumed to contain the HBOX element: George 4287 1998 because the associated style sheet is: HBOX { display: table-row } VBOX { display: table-cell } Example(s): In this example, three 'table-cell' elements are assumed to contain the text in the ROWs. Note that the text is further encapsulated in anonymous inline boxes, as explained in visual formatting model: This is the top row. This is the middle row. This is the bottom row. The style sheet is: STACK { display: inline-table } ROW { display: table-row } D { display: inline; font-weight: bolder } 17.3 Columns Table cells may belong to two contexts: rows and columns. However, in the source document cells are descendants of rows, never of columns. Nevertheless, some aspects of cells can be influenced by setting properties on columns. The following properties apply to column and column-group elements: 'border' The various border properties apply to columns only if 'border-collapse' is set to 'collapse' on the table element. In that case, borders set on columns and column groups are input to the conflict resolution algorithm that selects the border styles at every cell edge. 'background' The background properties set the background for cells in the column, but only if both the cell and row have transparent backgrounds. See "Table layers and transparency." 'width' The 'width' property gives the minimum width for the column. 'visibility' If the 'visibility' of a column is set to 'collapse', none of the cells in the column are rendered, and cells that span into other columns are clipped. In addition, the width of the table is diminished by the width the column would have taken up. See "Dynamic effects" below. Other values for 'visibility' have no effect. Example(s): Here are some examples of style rules that set properties on columns. The first two rules together implement the "rules" attribute of HTML 4 with a value of "cols". The third rule makes the "totals" column blue, the final two rules shows how to make a column a fixed size, by using the fixed layout algorithm. col { border-style: none solid } table { border-style: hidden } col.totals { background: blue } table { table-layout: fixed } col.totals { width: 5em } 17.4 Tables in the visual formatting model In terms of the visual formatting model, a table can behave like a block-level (for 'display: table') or inline-level (for 'display: inline-table') element. In both cases, the table generates a principal block box called the table wrapper box that contains the table box itself and any caption boxes (in document order). The table box is a block-level box that contains the table's internal table boxes. The caption boxes are block-level boxes that retain their own content, padding, margin, and border areas, and are rendered as normal block boxes inside the table wrapper box. Whether the caption boxes are placed before or after the table box is decided by the 'caption-side' property, as described below. The table wrapper box is a 'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level. The table wrapper box establishes a block formatting context. The table box (not the table wrapper box) is used when doing baseline vertical alignment for an 'inline-table'. The width of the table wrapper box is the border-edge width of the table box inside it, as described by section 17.5.2. Percentages on 'width' and 'height' on the table are relative to the table wrapper box's containing block, not the table wrapper box itself. The computed values of properties 'position', 'float', 'margin-*', 'top', 'right', 'bottom', and 'left' on the table element are used on the table wrapper box and not the table box; all other values of non-inheritable properties are used on the table box and not the table wrapper box. (Where the table element's values are not used on the table and table wrapper boxes, the initial values are used instead.) A table with a caption above it Diagram of a table with a caption above it. 17.4.1 Caption position and alignment 'caption-side' Value: top | bottom | inherit Initial: top Applies to: 'table-caption' elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified This property specifies the position of the caption box with respect to the table box. Values have the following meanings: top Positions the caption box above the table box. bottom Positions the caption box below the table box. Note: CSS2 described a different width and horizontal alignment behavior. That behavior will be introduced in CSS3 using the values 'top-outside' and 'bottom-outside' on this property. To align caption content horizontally within the caption box, use the 'text-align' property. Example(s): In this example, the 'caption-side' property places captions below tables. The caption will be as wide as the parent of the table, and caption text will be left-justified. caption { caption-side: bottom; width: auto; text-align: left } 17.5 Visual layout of table contents Internal table elements generate rectangular boxes with content and borders. Cells have padding as well. Internal table elements do not have margins. The visual layout of these boxes is governed by a rectangular, irregular grid of rows and columns. Each box occupies a whole number of grid cells, determined according to the following rules. These rules do not apply to HTML 4 or earlier HTML versions; HTML imposes its own limitations on row and column spans. 1. Each row box occupies one row of grid cells. Together, the row boxes fill the table from top to bottom in the order they occur in the source document (i.e., the table occupies exactly as many grid rows as there are row elements). 2. A row group occupies the same grid cells as the rows it contains. 3. A column box occupies one or more columns of grid cells. Column boxes are placed next to each other in the order they occur. The first column box may be either on the left or on the right, depending on the value of the 'direction' property of the table. 4. A column group box occupies the same grid cells as the columns it contains. 5. Cells may span several rows or columns. (Although CSS 2.1 does not define how the number of spanned rows or columns is determined, a user agent may have special knowledge about the source document; a future update of CSS may provide a way to express this knowledge in CSS syntax.) Each cell is thus a rectangular box, one or more grid cells wide and high. The top row of this rectangle is in the row specified by the cell's parent. The rectangle must be as far to the left as possible, but the part of the cell in the first column it occupies must not overlap with any other cell box (i.e., a row-spanning cell starting in a prior row), and the cell must be to the right of all cells in the same row that are earlier in the source document. If this position would cause a column-spanning cell to overlap a row-spanning cell from a prior row, CSS does not define the results: implementations may either overlap the cells (as is done in many HTML implementations) or may shift the later cell to the right to avoid such overlap. (This constraint holds if the 'direction' property of the table is 'ltr'; if the 'direction' is 'rtl', interchange "left" and "right" in the previous two sentences.) 6. A cell box cannot extend beyond the last row box of a table or row group; the user agents must shorten it until it fits. The edges of the rows, columns, row groups and column groups in the collapsing borders model coincide with the hypothetical grid lines on which the borders of the cells are centered. (And thus, in this model, the rows together exactly cover the table, leaving no gaps; ditto for the columns.) In the separated borders model, the edges coincide with the border edges of cells. (And thus, in this model, there may be gaps between the rows, columns, row groups or column groups, corresponding to the 'border-spacing' property.) Note. Positioning and floating of table cells can cause them not to be table cells anymore, according to the rules in section 9.7. When floating is used, the rules on anonymous table objects may cause an anonymous cell object to be created as well. Here is an example illustrating rule 5. The following illegal (X)HTML snippet defines conflicting cells: User agents are free to visually overlap the cells, as in the figure on the left, or to shift the cell to avoid the visual overlap, as in the figure on the right. One table with overlapping cells and one without [D] Two possible renderings of an erroneous HTML table. 17.5.1 Table layers and transparency For the purposes of finding the background of each table cell, the different table elements may be thought of as being on six superimposed layers. The background set on an element in one of the layers will only be visible if the layers above it have a transparent background. schema of table layers [D] Schema of table layers. 1. The lowest layer is a single plane, representing the table box itself. Like all boxes, it may be transparent. 2. The next layer contains the column groups. Each column group extends from the top of the cells in the top row to the bottom of the cells on the bottom row and from the left edge of its leftmost column to the right edge of its rightmost column. The background covers exactly the full area of all cells that originate in the column group, even if they span outside the column group, but this difference in area does not affect background image positioning. 3. On top of the column groups are the areas representing the column boxes. Each column is as tall as the column groups and as wide as a normal (single-column-spanning) cell in the column. The background covers exactly the full area of all cells that originate in the column, even if they span outside the column, but this difference in area does not affect background image positioning. 4. Next is the layer containing the row groups. Each row group extends from the top left corner of its topmost cell in the first column to the bottom right corner of its bottommost cell in the last column. 5. The next to last layer contains the rows. Each row is as wide as the row groups and as tall as a normal (single-row-spanning) cell in the row. As with columns, the background covers exactly the full area of all cells that originate in the row, even if they span outside the row, but this difference in area does not affect background image positioning. 6. The topmost layer contains the cells themselves. As the figure shows, although all rows contain the same number of cells, not every cell may have specified content. In the separated borders model ('border-collapse' is 'separate'), if the value of their 'empty-cells' property is 'hide' these "empty" cells are transparent through the cell, row, row group, column and column group backgrounds, letting the table background show through. A "missing cell" is a cell in the row/column grid that is not occupied by an element or pseudo-element. Missing cells are rendered as if an anonymous table-cell box occupied their position in the grid. In the following example, the first row contains four non-empty cells, but the second row contains only one non-empty cell, and thus the table background shines through, except where a cell from the first row spans into this row. The following HTML code and style rules Table example might be formatted as follows: Table with three empty cells in bottom row [D] Table with empty cells in the bottom row. Note that if the table has 'border-collapse: separate', the background of the area given by the 'border-spacing' property is always the background of the table element. See the separated borders model. 17.5.2 Table width algorithms: the 'table-layout' property CSS does not define an "optimal" layout for tables since, in many cases, what is optimal is a matter of taste. CSS does define constraints that user agents must respect when laying out a table. User agents may use any algorithm they wish to do so, and are free to prefer rendering speed over precision, except when the "fixed layout algorithm" is selected. Note that this section overrides the rules that apply to calculating widths as described in section 10.3. In particular, if the margins of a table are set to '0' and the width to 'auto', the table will not automatically size to fill its containing block. However, once the calculated value of 'width' for the table is found (using the algorithms given below or, when appropriate, some other UA dependent algorithm) then the other parts of section 10.3 do apply. Therefore a table can be centered using left and right 'auto' margins, for instance. Future updates of CSS may introduce ways of making tables automatically fit their containing blocks. 'table-layout' Value: auto | fixed | inherit Initial: auto Applies to: 'table' and 'inline-table' elements Inherited: no Percentages: N/A Media: visual Computed value: as specified The 'table-layout' property controls the algorithm used to lay out the table cells, rows, and columns. Values have the following meaning: fixed Use the fixed table layout algorithm auto Use any automatic table layout algorithm The two algorithms are described below. 17.5.2.1 Fixed table layout With this (fast) algorithm, the horizontal layout of the table does not depend on the contents of the cells; it only depends on the table's width, the width of the columns, and borders or cell spacing. The table's width may be specified explicitly with the 'width' property. A value of 'auto' (for both 'display: table' and 'display: inline-table') means use the automatic table layout algorithm. However, if the table is a block-level table ('display: table') in normal flow, a UA may (but does not have to) use the algorithm of 10.3.3 to compute a width and apply fixed table layout even if the specified width is 'auto'. Example(s): If a UA supports fixed table layout when 'width' is 'auto', the following will create a table that is 4em narrower than its containing block: table { table-layout: fixed; margin-left: 2em; margin-right: 2em } In the fixed table layout algorithm, the width of each column is determined as follows: 1. A column element with a value other than 'auto' for the 'width' property sets the width for that column. 2. Otherwise, a cell in the first row with a value other than 'auto' for the 'width' property determines the width for that column. If the cell spans more than one column, the width is divided over the columns. 3. Any remaining columns equally divide the remaining horizontal table space (minus borders or cell spacing). The width of the table is then the greater of the value of the 'width' property for the table element and the sum of the column widths (plus cell spacing or borders). If the table is wider than the columns, the extra space should be distributed over the columns. If a subsequent row has more columns than the greater of the number determined by the table-column elements and the number determined by the first row, then additional columns may not be rendered. CSS 2.1 does not define the width of the columns and the table if they are rendered. When using 'table-layout: fixed', authors should not omit columns from the first row. In this manner, the user agent can begin to lay out the table once the entire first row has been received. Cells in subsequent rows do not affect column widths. Any cell that has content that overflows uses the 'overflow' property to determine whether to clip the overflow content. 17.5.2.2 Automatic table layout In this algorithm (which generally requires no more than two passes), the table's width is given by the width of its columns (and intervening borders). This algorithm reflects the behavior of several popular HTML user agents at the writing of this specification. UAs are not required to implement this algorithm to determine the table layout in the case that 'table-layout' is 'auto'; they can use any other algorithm even if it results in different behavior. Input to the automatic table layout must only include the width of the containing block and the content of, and any CSS properties set on, the table and any of its descendants. Note. This may be defined in more detail in CSS3. The remainder of this section is non-normative. This algorithm may be inefficient since it requires the user agent to have access to all the content in the table before determining the final layout and may demand more than one pass. Column widths are determined as follows: 1. Calculate the minimum content width (MCW) of each cell: the formatted content may span any number of lines but may not overflow the cell box. If the specified 'width' (W) of the cell is greater than MCW, W is the minimum cell width. A value of 'auto' means that MCW is the minimum cell width. Also, calculate the "maximum" cell width of each cell: formatting the content without breaking lines other than where explicit line breaks occur. 2. For each column, determine a maximum and minimum column width from the cells that span only that column. The minimum is that required by the cell with the largest minimum cell width (or the column 'width', whichever is larger). The maximum is that required by the cell with the largest maximum cell width (or the column 'width', whichever is larger). 3. For each cell that spans more than one column, increase the minimum widths of the columns it spans so that together, they are at least as wide as the cell. Do the same for the maximum widths. If possible, widen all spanned columns by approximately the same amount. 4. For each column group element with a 'width' other than 'auto', increase the minimum widths of the columns it spans, so that together they are at least as wide as the column group's 'width'. This gives a maximum and minimum width for each column. The caption width minimum (CAPMIN) is determined by calculating for each caption the minimum caption outer width as the MCW of a hypothetical table cell that contains the caption formatted as "display: block". The greatest of the minimum caption outer widths is CAPMIN. Column and caption widths influence the final table width as follows: 1. If the 'table' or 'inline-table' element's 'width' property has a computed value (W) other than 'auto', the used width is the greater of W, CAPMIN, and the minimum width required by all the columns plus cell spacing or borders (MIN). If the used width is greater than MIN, the extra width should be distributed over the columns. 2. If the 'table' or 'inline-table' element has 'width: auto', the used width is the greater of the table's containing block width, CAPMIN, and MIN. However, if either CAPMIN or the maximum width required by the columns plus cell spacing or borders (MAX) is less than that of the containing block, use max(MAX, CAPMIN). A percentage value for a column width is relative to the table width. If the table has 'width: auto', a percentage represents a constraint on the column's width, which a UA should try to satisfy. (Obviously, this is not always possible: if the column's width is '110%', the constraint cannot be satisfied.) Note. In this algorithm, rows (and row groups) and columns (and column groups) both constrain and are constrained by the dimensions of the cells they contain. Setting the width of a column may indirectly influence the height of a row, and vice versa. 17.5.3 Table height algorithms The height of a table is given by the 'height' property for the 'table' or 'inline-table' element. A value of 'auto' means that the height is the sum of the row heights plus any cell spacing or borders. Any other value is treated as a minimum height. CSS 2.1 does not define how extra space is distributed when the 'height' property causes the table to be taller than it otherwise would be. Note. Future updates of CSS may specify this further. The height of a 'table-row' element's box is calculated once the user agent has all the cells in the row available: it is the maximum of the row's computed 'height', the computed 'height' of each cell in the row, and the minimum height (MIN) required by the cells. A 'height' value of 'auto' for a 'table-row' means the row height used for layout is MIN. MIN depends on cell box heights and cell box alignment (much like the calculation of a line box height). CSS 2.1 does not define how the height of table cells and table rows is calculated when their height is specified using percentage values. CSS 2.1 does not define the meaning of 'height' on row groups. In CSS 2.1, the height of a cell box is the minimum height required by the content. The table cell's 'height' property can influence the height of the row (see above), but it does not increase the height of the cell box. CSS 2.1 does not specify how cells that span more than one row affect row height calculations except that the sum of the row heights involved must be great enough to encompass the cell spanning the rows. The 'vertical-align' property of each table cell determines its alignment within the row. Each cell's content has a baseline, a top, a middle, and a bottom, as does the row itself. In the context of tables, values for 'vertical-align' have the following meanings: baseline The baseline of the cell is put at the same height as the baseline of the first of the rows it spans (see below for the definition of baselines of cells and rows). top The top of the cell box is aligned with the top of the first row it spans. bottom The bottom of the cell box is aligned with the bottom of the last row it spans. middle The center of the cell is aligned with the center of the rows it spans. sub, super, text-top, text-bottom, , These values do not apply to cells; the cell is aligned at the baseline instead. The baseline of a cell is the baseline of the first in-flow line box in the cell, or the first in-flow table-row in the cell, whichever comes first. If there is no such line box or table-row, the baseline is the bottom of content edge of the cell box. For the purposes of finding a baseline, in-flow boxes with a scrolling mechanisms (see the 'overflow' property) must be considered as if scrolled to their origin position. Note that the baseline of a cell may end up below its bottom border, see the example below. The maximum distance between the top of the cell box and the baseline over all cells that have 'vertical-align: baseline' is used to set the baseline of the row. Here is an example: Example of vertically aligning the cells [D] Diagram showing the effect of various values of 'vertical-align' on table cells. Cell boxes 1 and 2 are aligned at their baselines. Cell box 2 has the largest height above the baseline, so that determines the baseline of the row. If a row has no cell box aligned to its baseline, the baseline of that row is the bottom content edge of the lowest cell in the row. To avoid ambiguous situations, the alignment of cells proceeds in the following order: 1. First the cells that are aligned on their baseline are positioned. This will establish the baseline of the row. Next the cells with 'vertical-align: top' are positioned. 2. The row now has a top, possibly a baseline, and a provisional height, which is the distance from the top to the lowest bottom of the cells positioned so far. (See conditions on the cell padding below.) 3. If any of the remaining cells, those aligned at the bottom or the middle, have a height that is larger than the current height of the row, the height of the row will be increased to the maximum of those cells, by lowering the bottom. 4. Finally the remaining cells are positioned. Cell boxes that are smaller than the height of the row receive extra top or bottom padding. The cell in this example has a baseline below its bottom border: div { height: 0; overflow: hidden; } 17.5.4 Horizontal alignment in a column The horizontal alignment of inline-level content within a cell box can be specified by the value of the 'text-align' property on the cell. 17.5.5 Dynamic row and column effects The 'visibility' property takes the value 'collapse' for row, row group, column, and column group elements. This value causes the entire row or column to be removed from the display, and the space normally taken up by the row or column to be made available for other content. Contents of spanned rows and columns that intersect the collapsed column or row are clipped. The suppression of the row or column, however, does not otherwise affect the layout of the table. This allows dynamic effects to remove table rows or columns without forcing a re-layout of the table in order to account for the potential change in column constraints. 17.6 Borders There are two distinct models for setting borders on table cells in CSS. One is most suitable for so-called separated borders around individual cells, the other is suitable for borders that are continuous from one end of the table to the other. Many border styles can be achieved with either model, so it is often a matter of taste which one is used. 'border-collapse' Value: collapse | separate | inherit Initial: separate Applies to: 'table' and 'inline-table' elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified This property selects a table's border model. The value 'separate' selects the separated borders border model. The value 'collapse' selects the collapsing borders model. The models are described below. 17.6.1 The separated borders model 'border-spacing' Value: ? | inherit Initial: 0 Applies to: 'table' and 'inline-table' elements* Inherited: yes Percentages: N/A Media: visual Computed value: two absolute lengths *) Note: user agents may also apply the 'border-spacing' property to 'frameset' elements. Which elements are 'frameset' elements is not defined by this specification and is up to the document language. For example, HTML4 defines a element, and XHTML 1.0 defines a element. The 'border-spacing' property on a 'frameset' element can be thus used as a valid substitute for the non-standard 'framespacing' attribute. The lengths specify the distance that separates adjoining cell borders. If one length is specified, it gives both the horizontal and vertical spacing. If two are specified, the first gives the horizontal spacing and the second the vertical spacing. Lengths may not be negative. The distance between the table border and the borders of the cells on the edge of the table is the table's padding for that side, plus the relevant border spacing distance. For example, on the right hand side, the distance is padding-right + horizontal border-spacing. The width of the table is the distance from the left inner padding edge to the right inner padding edge (including the border spacing but excluding padding and border). However, in HTML and XHTML1, the width of the element is the distance from the left border edge to the right border edge. Note: In CSS3 this peculiar requirement will be defined in terms of UA style sheet rules and the 'box-sizing' property. In this model, each cell has an individual border. The 'border-spacing' property specifies the distance between the borders of adjoining cells. In this space, the row, column, row group, and column group backgrounds are invisible, allowing the table background to show through. Rows, columns, row groups, and column groups cannot have borders (i.e., user agents must ignore the border properties for those elements). Example(s): The table in the figure below could be the result of a style sheet like this: table { border: outset 10pt; border-collapse: separate; border-spacing: 15pt } td { border: inset 5pt } td.special { border: inset 10pt } /* The top-left cell */ A table with border-spacing [D] A table with 'border-spacing' set to a length value. Note that each cell has its own border, and the table has a separate border as well. 17.6.1.1 Borders and Backgrounds around empty cells: the 'empty-cells' property 'empty-cells' Value: show | hide | inherit Initial: show Applies to: 'table-cell' elements Inherited: yes Percentages: N/A Media: visual Computed value: as specified In the separated borders model, this property controls the rendering of borders and backgrounds around cells that have no visible content. Empty cells and cells with the 'visibility' property set to 'hidden' are considered to have no visible content. Cells are empty unless they contain one or more of the following: * floating content (including empty elements), * in-flow content (including empty elements) other than white space that has been collapsed away by the 'white-space' property handling. When this property has the value 'show', borders and backgrounds are drawn around/behind empty cells (like normal cells). A value of 'hide' means that no borders or backgrounds are drawn around/behind empty cells (see point 6 in 17.5.1). Furthermore, if all the cells in a row have a value of 'hide' and have no visible content, then the row has zero height and there is vertical border-spacing on only one side of the row. Example(s): The following rule causes borders and backgrounds to be drawn around all cells: table { empty-cells: show } 17.6.2 The collapsing border model In the collapsing border model, it is possible to specify borders that surround all or part of a cell, row, row group, column, and column group. Borders for HTML's "rules" attribute can be specified this way. Borders are centered on the grid lines between the cells. User agents must find a consistent rule for rounding off in the case of an odd number of discrete units (screen pixels, printer dots). The diagram below shows how the width of the table, the widths of the borders, the padding, and the cell width interact. Their relation is given by the following equation, which holds for every row of the table: row-width = (0.5 * border-width[0]) + padding-left[1] + width[1] + padding-right[1] + border-width[1] + padding-left[2] +...+ padding-right[n] + (0.5 * border-width[n]) Here n is the number of cells in the row, padding-left[i] and padding-right[i] refer to the left (resp., right) padding of cell i, and border-width[i] refers to the border between cells i and i + 1. UAs must compute an initial left and right border width for the table by examining the first and last cells in the first row of the table. The left border width of the table is half of the first cell's collapsed left border, and the right border width of the table is half of the last cell's collapsed right border. If subsequent rows have larger collapsed left and right borders, then any excess spills into the margin area of the table. The top border width of the table is computed by examining all cells who collapse their top borders with the top border of the table. The top border width of the table is equal to half of the maximum collapsed top border. The bottom border width is computed by examining all cells whose bottom borders collapse with the bottom of the table. The bottom border width is equal to half of the maximum collapsed bottom border. Any borders that spill into the margin are taken into account when determining if the table overflows some ancestor (see 'overflow'). Schema showing the widths of cells and borders and the padding of cells [D] Schema showing the widths of cells and borders and the padding of cells. Note that in this model, the width of the table includes half the table border. Also, in this model, a table does not have padding (but does have margins). CSS 2.1 does not define where the edge of a background on a table element lies. 17.6.2.1 Border conflict resolution In the collapsing border model, borders at every edge of every cell may be specified by border properties on a variety of elements that meet at that edge (cells, rows, row groups, columns, column groups, and the table itself), and these borders may vary in width, style, and color. The rule of thumb is that at each edge the most "eye catching" border style is chosen, except that any occurrence of the style 'hidden' unconditionally turns the border off. The following rules determine which border style "wins" in case of a conflict: 1. Borders with the 'border-style' of 'hidden' take precedence over all other conflicting borders. Any border with this value suppresses all borders at this location. 2. Borders with a style of 'none' have the lowest priority. Only if the border properties of all the elements meeting at this edge are 'none' will the border be omitted (but note that 'none' is the default value for the border style.) 3. If none of the styles are 'hidden' and at least one of them is not 'none', then narrow borders are discarded in favor of wider ones. If several have the same 'border-width' then styles are preferred in this order: 'double', 'solid', 'dashed', 'dotted', 'ridge', 'outset', 'groove', and the lowest: 'inset'. 4. If border styles differ only in color, then a style set on a cell wins over one on a row, which wins over a row group, column, column group and, lastly, table. When two elements of the same type conflict, then the one further to the left (if the table's 'direction' is 'ltr'; right, if it is 'rtl') and further to the top wins. Example(s): The following example illustrates the application of these precedence rules. This style sheet: table { border-collapse: collapse; border: 5px solid yellow; } *#col1 { border: 3px solid black; } td { border: 1px solid red; padding: 1em; } td.cell5 { border: 5px dashed blue; } td.cell6 { border: 5px solid green; } with this HTML source: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 would produce something like this: An example of a table with collapsed borders [D] An example of a table with collapsed borders. Example(s): Here is an example of hidden collapsing borders: Table with two omitted borders [D] Table with two omitted internal borders. HTML source: 17.6.3 Border styles Some of the values of the 'border-style' have different meanings in tables than for other elements. In the list below they are marked with an asterisk. none No border. *hidden Same as 'none', but in the collapsing border model, also inhibits any other border (see the section on border conflicts). dotted The border is a series of dots. dashed The border is a series of short line segments. solid The border is a single line segment. double The border is two solid lines. The sum of the two lines and the space between them equals the value of 'border-width'. groove The border looks as though it were carved into the canvas. ridge The opposite of 'groove': the border looks as though it were coming out of the canvas. *inset In the separated borders model, the border makes the entire box look as though it were embedded in the canvas. In the collapsing border model, drawn the same as 'ridge'. *outset In the separated borders model, the border makes the entire box look as though it were coming out of the canvas. In the collapsing border model, drawn the same as 'groove'. 18 User interface Contents * 18.1 Cursors: the 'cursor' property * 18.2 System Colors * 18.3 User preferences for fonts * 18.4 Dynamic outlines: the 'outline' property + 18.4.1 Outlines and the focus * 18.5 Magnification 18.1 Cursors: the 'cursor' property 'cursor' Value: [ [ ,]* [ auto | crosshair | default | pointer | move | e-resize | ne-resize | nw-resize | n-resize | se-resize | sw-resize | s-resize | w-resize | text | wait | help | progress ] ] | inherit Initial: auto Applies to: all elements Inherited: yes Percentages: N/A Media: visual, interactive Computed value: as specified, except with any relative URLs converted to absolute This property specifies the type of cursor to be displayed for the pointing device. Values have the following meanings: auto The UA determines the cursor to display based on the current context. crosshair A simple crosshair (e.g., short line segments resembling a "+" sign). default The platform-dependent default cursor. Often rendered as an arrow. pointer The cursor is a pointer that indicates a link. move Indicates something is to be moved. e-resize, ne-resize, nw-resize, n-resize, se-resize, sw-resize, s-resize, w-resize Indicate that some edge is to be moved. For example, the 'se-resize' cursor is used when the movement starts from the south-east corner of the box. text Indicates text that may be selected. Often rendered as an I-beam. wait Indicates that the program is busy and the user should wait. Often rendered as a watch or hourglass. progress A progress indicator. The program is performing some processing, but is different from 'wait' in that the user may still interact with the program. Often rendered as a spinning beach ball, or an arrow with a watch or hourglass. help Help is available for the object under the cursor. Often rendered as a question mark or a balloon. The user agent retrieves the cursor from the resource designated by the URI. If the user agent cannot handle the first cursor of a list of cursors, it should attempt to handle the second, etc. If the user agent cannot handle any user-defined cursor, it must use the generic cursor at the end of the list. Intrinsic sizes for cursors are calculated as for background images, except that a UA-defined rectangle is used in place of the rectangle that establishes the coordinate system for the 'background-image' property. This UA-defined rectangle should be based on the size of a typical cursor on the UA's operating system. If the resulting cursor size does not fit within this rectangle, the UA may proportionally scale the resulting cursor down until it fits within the rectangle. Example(s): :link,:visited { cursor: url(example.svg#linkcursor), url(hyper.cur), pointer } This example sets the cursor on all hyperlinks (whether visited or not) to an external SVG cursor. User agents that do not support SVG cursors would simply skip to the next value and attempt to use the "hyper.cur" cursor. If that cursor format was also not supported, the UA would skip to the next value and simply render the 'pointer' cursor. 18.2 System Colors Note. The System Colors are deprecated in the CSS3 Color Module [CSS3COLOR]. In addition to being able to assign pre-defined color values to text, backgrounds, etc., CSS2 introduced a set of named color values that allows authors to specify colors in a manner that integrates them into the operating system's graphic environment. For systems that do not have a corresponding value, the specified value should be mapped to the nearest system value, or to a default color. The following lists additional values for color-related CSS properties and their general meaning. Any color property (e.g., 'color' or 'background-color') can take one of the following names. Although these are case-insensitive, it is recommended that the mixed capitalization shown below be used, to make the names more legible. ActiveBorder Active window border. ActiveCaption Active window caption. AppWorkspace Background color of multiple document interface. Background Desktop background. ButtonFace Face color for three-dimensional display elements. ButtonHighlight Highlight color for three-dimensional display elements (for edges facing away from the light source). ButtonShadow Shadow color for three-dimensional display elements. ButtonText Text on push buttons. CaptionText Text in caption, size box, and scrollbar arrow box. GrayText Grayed (disabled) text. This color is set to #000 if the current display driver does not support a solid gray color. Highlight Item(s) selected in a control. HighlightText Text of item(s) selected in a control. InactiveBorder Inactive window border. InactiveCaption Inactive window caption. InactiveCaptionText Color of text in an inactive caption. InfoBackground Background color for tooltip controls. InfoText Text color for tooltip controls. Menu Menu background. MenuText Text in menus. Scrollbar Scroll bar gray area. ThreeDDarkShadow Dark shadow for three-dimensional display elements. ThreeDFace Face color for three-dimensional display elements. ThreeDHighlight Highlight color for three-dimensional display elements. ThreeDLightShadow Light color for three-dimensional display elements (for edges facing the light source). ThreeDShadow Dark shadow for three-dimensional display elements. Window Window background. WindowFrame Window frame. WindowText Text in windows. Example(s): For example, to set the foreground and background colors of a paragraph to the same foreground and background colors of the user's window, write the following: p { color: WindowText; background-color: Window } 18.3 User preferences for fonts As for colors, authors may specify fonts in a way that makes use of a user's system resources. Please consult the 'font' property for details. 18.4 Dynamic outlines: the 'outline' property At times, style sheet authors may want to create outlines around visual objects such as buttons, active form fields, image maps, etc., to make them stand out. CSS 2.1 outlines differ from borders in the following ways: 1. Outlines do not take up space. 2. Outlines may be non-rectangular. The outline properties control the style of these dynamic outlines. 'outline' Value: [ <'outline-color'> || <'outline-style'> || <'outline-width'> ] | inherit Initial: see individual properties Applies to: all elements Inherited: no Percentages: N/A Media: visual, interactive Computed value: see individual properties 'outline-width' Value: | inherit Initial: medium Applies to: all elements Inherited: no Percentages: N/A Media: visual, interactive Computed value: absolute length; '0' if the outline style is 'none' 'outline-style' Value: | inherit Initial: none Applies to: all elements Inherited: no Percentages: N/A Media: visual, interactive Computed value: as specified 'outline-color' Value: | invert | inherit Initial: invert Applies to: all elements Inherited: no Percentages: N/A Media: visual, interactive Computed value: as specified The outline created with the outline properties is drawn "over" a box, i.e., the outline is always on top, and does not influence the position or size of the box, or of any other boxes. Therefore, displaying or suppressing outlines does not cause reflow or overflow. The outline may be drawn starting just outside the border edge. Outlines may be non-rectangular. For example, if the element is broken across several lines, the outline is the minimum outline that encloses all the element's boxes. In contrast to borders, the outline is not open at the line box's end or start, but is always fully connected if possible. The 'outline-width' property accepts the same values as 'border-width'. The 'outline-style' property accepts the same values as 'border-style', except that 'hidden' is not a legal outline style. The 'outline-color' accepts all colors, as well as the keyword 'invert'. 'Invert' is expected to perform a color inversion on the pixels on the screen. This is a common trick to ensure the focus border is visible, regardless of color background. Conformant UAs may ignore the 'invert' value on platforms that do not support color inversion of the pixels on the screen. If the UA does not support the 'invert' value then the initial value of the 'outline-color' property is the value of the 'color' property, similar to the initial value of the 'border-top-color' property. The 'outline' property is a shorthand property, and sets all three of 'outline-style', 'outline-width', and 'outline-color'. Note. The outline is the same on all sides. In contrast to borders, there is no 'outline-top' or 'outline-left' property. This specification does not define how multiple overlapping outlines are drawn, or how outlines are drawn for boxes that are partially obscured behind other elements. Note. Since the outline does not affect formatting (i.e., no space is left for it in the box model), it may well overlap other elements on the page. Example(s): Here's an example of drawing a thick outline around a BUTTON element: button { outline : thick solid} Scripts may be used to dynamically change the width of the outline, without provoking a reflow. 18.4.1 Outlines and the focus Graphical user interfaces may use outlines around elements to tell the user which element on the page has the focus. These outlines are in addition to any borders, and switching outlines on and off should not cause the document to reflow. The focus is the subject of user interaction in a document (e.g., for entering text, selecting a button, etc.). User agents supporting the interactive media group must keep track of where the focus lies and must also represent the focus. This may be done by using dynamic outlines in conjunction with the :focus pseudo-class. Example(s): For example, to draw a thick black line around an element when it has the focus, and a thick red line when it is active, the following rules can be used: :focus { outline: thick solid black } :active { outline: thick solid red } 18.5 Magnification The CSS working group considers that the magnification of a document or portions of a document should not be specified through style sheets. User agents may support such magnification in different ways (e.g., larger images, louder sounds, etc.) When magnifying a page, UAs should preserve the relationships between positioned elements. For example, a comic strip may be composed of images with overlaid text elements. When magnifying this page, a user agent should keep the text within the comic strip balloon. Appendix A. Aural style sheets Contents * A.1 The media types 'aural' and 'speech' * A.2 Introduction to aural style sheets + A.2.1 Angles + A.2.2 Times + A.2.3 Frequencies * A.3 Volume properties: 'volume' * A.4 Speaking properties: 'speak' * A.5 Pause properties: 'pause-before', 'pause-after', and 'pause' * A.6 Cue properties: 'cue-before', 'cue-after', and 'cue' * A.7 Mixing properties: 'play-during' * A.8 Spatial properties: 'azimuth' and 'elevation' * A.9 Voice characteristic properties: 'speech-rate', 'voice-family', 'pitch', 'pitch-range', 'stress', and 'richness' * A.10 Speech properties: 'speak-punctuation' and 'speak-numeral' * A.11 Audio rendering of tables + A.11.1 Speaking headers: the 'speak-header' property * A.12 Sample style sheet for HTML * A.13 Emacspeak This chapter is informative. UAs are not required to implement the properties of this chapter in order to conform to CSS 2.1. A.1 The media types 'aural' and 'speech' We expect that in a future level of CSS there will be new properties and values defined for speech output. Therefore CSS 2.1 reserves the 'speech' media type (see chapter 7, "Media types"), but does not yet define which properties do or do not apply to it. The properties in this appendix apply to a media type 'aural', that was introduced in CSS2. The type 'aural' is now deprecated. This means that a style sheet such as @media speech { body { voice-family: Paul } } is valid, but that its meaning is not defined by CSS 2.1, while @media aural { body { voice-family: Paul } } is deprecated, but defined by this appendix. A.2 Introduction to aural style sheets The aural rendering of a document, already commonly used by the blind and print-impaired communities, combines speech synthesis and "auditory icons." Often such aural presentation occurs by converting the document to plain text and feeding this to a screen reader -- software or hardware that simply reads all the characters on the screen. This results in less effective presentation than would be the case if the document structure were retained. Style sheet properties for aural presentation may be used together with visual properties (mixed media) or as an aural alternative to visual presentation. Besides the obvious accessibility advantages, there are other large markets for listening to information, including in-car use, industrial and medical documentation systems (intranets), home entertainment, and to help users learning to read or who have difficulty reading. When using aural properties, the canvas consists of a three-dimensional physical space (sound surrounds) and a temporal space (one may specify sounds before, during, and after other sounds). The CSS properties also allow authors to vary the quality of synthesized speech (voice type, frequency, inflection, etc.). Example(s): h1, h2, h3, h4, h5, h6 { voice-family: paul; stress: 20; richness: 90; cue-before: url("ping.au") } p.heidi { azimuth: center-left } p.peter { azimuth: right } p.goat { volume: x-soft } This will direct the speech synthesizer to speak headers in a voice (a kind of "audio font") called "paul", on a flat tone, but in a very rich voice. Before speaking the headers, a sound sample will be played from the given URL. Paragraphs with class "heidi" will appear to come from front left (if the sound system is capable of spatial audio), and paragraphs of class "peter" from the right. Paragraphs with class "goat" will be very soft. A.2.1 Angles Angle values are denoted by in the text. Their format is a immediately followed by an angle unit identifier. Angle unit identifiers are: * deg: degrees * grad: grads * rad: radians Angle values may be negative. They should be normalized to the range 0-360deg by the user agent. For example, -10deg and 350deg are equivalent. For example, a right angle is '90deg' or '100grad' or '1.570796326794897rad'. Like for , the unit may be omitted, if the value is zero: '0deg' may be written as '0'. A.2.2 Times Time values are denoted by in the text. Their format is a immediately followed by a time unit identifier. Time unit identifiers are: * ms: milliseconds * s: seconds Time values may not be negative. Like for , the unit may be omitted, if the value is zero: '0s' may be written as '0'. A.2.3 Frequencies Frequency values are denoted by in the text. Their format is a immediately followed by a frequency unit identifier. Frequency unit identifiers are: * Hz: Hertz * kHz: kilohertz Frequency values may not be negative. For example, 200Hz (or 200hz) is a bass sound, and 6kHz is a treble sound. Like for , the unit may be omitted, if the value is zero: '0Hz' may be written as '0'. A.3 Volume properties: 'volume' 'volume' Value: | | silent | x-soft | soft | medium | loud | x-loud | inherit Initial: medium Applies to: all elements Inherited: yes Percentages: refer to inherited value Media: aural Computed value: number Volume refers to the median volume of the waveform. In other words, a highly inflected voice at a volume of 50 might peak well above that. The overall values are likely to be human adjustable for comfort, for example with a physical volume control (which would increase both the 0 and 100 values proportionately); what this property does is adjust the dynamic range. Values have the following meanings: Any number between '0' and '100'. '0' represents the minimum audible volume level and 100 corresponds to the maximum comfortable level. Percentage values are calculated relative to the inherited value, and are then clipped to the range '0' to '100'. silent No sound at all. The value '0' does not mean the same as 'silent'. x-soft Same as '0'. soft Same as '25'. medium Same as '50'. loud Same as '75'. x-loud Same as '100'. User agents should allow the values corresponding to '0' and '100' to be set by the listener. No one setting is universally applicable; suitable values depend on the equipment in use (speakers, headphones), the environment (in car, home theater, library) and personal preferences. Some examples: * A browser for in-car use has a setting for when there is lots of background noise. '0' would map to a fairly high level and '100' to a quite high level. The speech is easily audible over the road noise but the overall dynamic range is compressed. Cars with better insulation might allow a wider dynamic range. * Another speech browser is being used in an apartment, late at night, or in a shared study room. '0' is set to a very quiet level and '100' to a fairly quiet level, too. As with the first example, there is a low slope; the dynamic range is reduced. The actual volumes are low here, whereas they were high in the first example. * In a quiet and isolated house, an expensive hi-fi home theater setup. '0' is set fairly low and '100' to quite high; there is wide dynamic range. The same author style sheet could be used in all cases, simply by mapping the '0' and '100' points suitably at the client side. A.4 Speaking properties: 'speak' 'speak' Value: normal | none | spell-out | inherit Initial: normal Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified This property specifies whether text will be rendered aurally and if so, in what manner. The possible values are: none Suppresses aural rendering so that the element requires no time to render. Note, however, that descendants may override this value and will be spoken. (To be sure to suppress rendering of an element and its descendants, use the 'display' property). normal Uses language-dependent pronunciation rules for rendering an element and its children. spell-out Spells the text one letter at a time (useful for acronyms and abbreviations). Note the difference between an element whose 'volume' property has a value of 'silent' and an element whose 'speak' property has the value 'none'. The former takes up the same time as if it had been spoken, including any pause before and after the element, but no sound is generated. The latter requires no time and is not rendered (though its descendants may be). A.5 Pause properties: 'pause-before', 'pause-after', and 'pause' 'pause-before' Value: | | inherit Initial: 0 Applies to: all elements Inherited: no Percentages: see prose Media: aural Computed value: time 'pause-after' Value: | | inherit Initial: 0 Applies to: all elements Inherited: no Percentages: see prose Media: aural Computed value: time;; These properties specify a pause to be observed before (or after) speaking an element's content. Values have the following meanings: Note. In CSS3 pauses are inserted around the cues and content rather than between them. See [CSS3SPEECH] for details. Expresses the pause in absolute time units (seconds and milliseconds). Refers to the inverse of the value of the 'speech-rate' property. For example, if the speech-rate is 120 words per minute (i.e., a word takes half a second, or 500ms) then a 'pause-before' of 100% means a pause of 500 ms and a 'pause-before' of 20% means 100ms. The pause is inserted between the element's content and any 'cue-before' or 'cue-after' content. Authors should use relative units to create more robust style sheets in the face of large changes in speech-rate. 'pause' Value: [ [ | ]{1,2} ] | inherit Initial: see individual properties Applies to: all elements Inherited: no Percentages: see descriptions of 'pause-before' and 'pause-after' Media: aural Computed value: see individual properties The 'pause' property is a shorthand for setting 'pause-before' and 'pause-after'. If two values are given, the first value is 'pause-before' and the second is 'pause-after'. If only one value is given, it applies to both properties. Example(s): h1 { pause: 20ms } /* pause-before: 20ms; pause-after: 20ms */ h2 { pause: 30ms 40ms } /* pause-before: 30ms; pause-after: 40ms */ h3 { pause-after: 10ms } /* pause-before unspecified; pause-after: 10ms */ A.6 Cue properties: 'cue-before', 'cue-after', and 'cue' 'cue-before' Value: | none | inherit Initial: none Applies to: all elements Inherited: no Percentages: N/A Media: aural Computed value: absolute URI or 'none' 'cue-after' Value: | none | inherit Initial: none Applies to: all elements Inherited: no Percentages: N/A Media: aural Computed value: absolute URI or 'none' Auditory icons are another way to distinguish semantic elements. Sounds may be played before and/or after the element to delimit it. Values have the following meanings: The URI must designate an auditory icon resource. If the URI resolves to something other than an audio file, such as an image, the resource should be ignored and the property treated as if it had the value 'none'. none No auditory icon is specified. Example(s): a {cue-before: url("bell.aiff"); cue-after: url("dong.wav") } h1 {cue-before: url("pop.au"); cue-after: url("pop.au") } 'cue' Value: [ <'cue-before'> || <'cue-after'> ] | inherit Initial: see individual properties Applies to: all elements Inherited: no Percentages: N/A Media: aural Computed value: see individual properties The 'cue' property is a shorthand for setting 'cue-before' and 'cue-after'. If two values are given, the first value is 'cue-before' and the second is 'cue-after'. If only one value is given, it applies to both properties. Example(s): The following two rules are equivalent: h1 {cue-before: url("pop.au"); cue-after: url("pop.au") } h1 {cue: url("pop.au") } If a user agent cannot render an auditory icon (e.g., the user's environment does not permit it), we recommend that it produce an alternative cue. Please see the sections on the :before and :after pseudo-elements for information on other content generation techniques. 'Cue-before' sounds and 'pause-before' gaps are inserted before content from the ':before' pseudo-element. Similarly, 'pause-after' gaps and 'cue-after' sounds are inserted after content from the ':after' pseudo-element. A.7 Mixing properties: 'play-during' 'play-during' Value: [ mix || repeat ]? | auto | none | inherit Initial: auto Applies to: all elements Inherited: no Percentages: N/A Media: aural Computed value: absolute URI, rest as specified Similar to the 'cue-before' and 'cue-after' properties, this property specifies a sound to be played as a background while an element's content is spoken. Values have the following meanings: The sound designated by this is played as a background while the element's content is spoken. mix When present, this keyword means that the sound inherited from the parent element's 'play-during' property continues to play and the sound designated by the is mixed with it. If 'mix' is not specified, the element's background sound replaces the parent's. repeat When present, this keyword means that the sound will repeat if it is too short to fill the entire duration of the element. Otherwise, the sound plays once and then stops. This is similar to the 'background-repeat' property. If the sound is too long for the element, it is clipped once the element has been spoken. auto The sound of the parent element continues to play (it is not restarted, which would have been the case if this property had been inherited). none This keyword means that there is silence. The sound of the parent element (if any) is silent during the current element and continues after the current element. Example(s): blockquote.sad { play-during: url("violins.aiff") } blockquote Q { play-during: url("harp.wav") mix } span.quiet { play-during: none } A.8 Spatial properties: 'azimuth' and 'elevation' Spatial audio is an important stylistic property for aural presentation. It provides a natural way to tell several voices apart, as in real life (people rarely all stand in the same spot in a room). Stereo speakers produce a lateral sound stage. Binaural headphones or the increasingly popular 5-speaker home theater setups can generate full surround sound, and multi-speaker setups can create a true three-dimensional sound stage. VRML 2.0 also includes spatial audio, which implies that in time consumer-priced spatial audio hardware will become more widely available. 'azimuth' Value: | [[ left-side | far-left | left | center-left | center | center-right | right | far-right | right-side ] || behind ] | leftwards | rightwards | inherit Initial: center Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: normalized angle Values have the following meanings: Position is described in terms of an angle within the range '-360deg' to '360deg'. The value '0deg' means directly ahead in the center of the sound stage. '90deg' is to the right, '180deg' behind, and '270deg' (or, equivalently and more conveniently, '-90deg') to the left. left-side Same as '270deg'. With 'behind', '270deg'. far-left Same as '300deg'. With 'behind', '240deg'. left Same as '320deg'. With 'behind', '220deg'. center-left Same as '340deg'. With 'behind', '200deg'. center Same as '0deg'. With 'behind', '180deg'. center-right Same as '20deg'. With 'behind', '160deg'. right Same as '40deg'. With 'behind', '140deg'. far-right Same as '60deg'. With 'behind', '120deg'. right-side Same as '90deg'. With 'behind', '90deg'. leftwards Moves the sound to the left, relative to the current angle. More precisely, subtracts 20 degrees. Arithmetic is carried out modulo 360 degrees. Note that 'leftwards' is more accurately described as "turned counter-clockwise," since it always subtracts 20 degrees, even if the inherited azimuth is already behind the listener (in which case the sound actually appears to move to the right). rightwards Moves the sound to the right, relative to the current angle. More precisely, adds 20 degrees. See 'leftwards' for arithmetic. This property is most likely to be implemented by mixing the same signal into different channels at differing volumes. It might also use phase shifting, digital delay, and other such techniques to provide the illusion of a sound stage. The precise means used to achieve this effect and the number of speakers used to do so are user agent-dependent; this property merely identifies the desired end result. Example(s): h1 { azimuth: 30deg } td.a { azimuth: far-right } /* 60deg */ #12 { azimuth: behind far-right } /* 120deg */ p.comment { azimuth: behind } /* 180deg */ If spatial-azimuth is specified and the output device cannot produce sounds behind the listening position, user agents should convert values in the rearwards hemisphere to forwards hemisphere values. One method is as follows: * if 90deg < x <= 180deg then x := 180deg - x * if 180deg < x <= 270deg then x := 540deg - x 'elevation' Value: | below | level | above | higher | lower | inherit Initial: level Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: normalized angle Values of this property have the following meanings: Specifies the elevation as an angle, between '-90deg' and '90deg'. '0deg' means on the forward horizon, which loosely means level with the listener. '90deg' means directly overhead and '-90deg' means directly below. below Same as '-90deg'. level Same as '0deg'. above Same as '90deg'. higher Adds 10 degrees to the current elevation. lower Subtracts 10 degrees from the current elevation. The precise means used to achieve this effect and the number of speakers used to do so are undefined. This property merely identifies the desired end result. Example(s): h1 { elevation: above } tr.a { elevation: 60deg } tr.b { elevation: 30deg } tr.c { elevation: level } A.9 Voice characteristic properties: 'speech-rate', 'voice-family', 'pitch', 'pitch-range', 'stress', and 'richness' 'speech-rate' Value: | x-slow | slow | medium | fast | x-fast | faster | slower | inherit Initial: medium Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: number This property specifies the speaking rate. Note that both absolute and relative keyword values are allowed (compare with 'font-size'). Values have the following meanings: Specifies the speaking rate in words per minute, a quantity that varies somewhat by language but is nevertheless widely supported by speech synthesizers. x-slow Same as 80 words per minute. slow Same as 120 words per minute medium Same as 180 - 200 words per minute. fast Same as 300 words per minute. x-fast Same as 500 words per minute. faster Adds 40 words per minute to the current speech rate. slower Subtracts 40 words per minutes from the current speech rate. 'voice-family' Value: [[ | ],]* [ | ] | inherit Initial: depends on user agent Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified The value is a comma-separated, prioritized list of voice family names (compare with 'font-family'). Values have the following meanings: Values are voice families. Possible values are 'male', 'female', and 'child'. Values are specific instances (e.g., comedian, trinoids, carlos, lani). Example(s): h1 { voice-family: announcer, male } p.part.romeo { voice-family: romeo, male } p.part.juliet { voice-family: juliet, female } Names of specific voices may be quoted, and indeed must be quoted if any of the words that make up the name does not conform to the syntax rules for identifiers. It is also recommended to quote specific voices with a name consisting of more than one word. If quoting is omitted, any white space characters before and after the voice family name are ignored and any sequence of white space characters inside the voice family name is converted to a single space. 'pitch' Value: | x-low | low | medium | high | x-high | inherit Initial: medium Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: frequency Specifies the average pitch (a frequency) of the speaking voice. The average pitch of a voice depends on the voice family. For example, the average pitch for a standard male voice is around 120Hz, but for a female voice, it's around 210Hz. Values have the following meanings: Specifies the average pitch of the speaking voice in hertz (Hz). x-low, low, medium, high, x-high These values do not map to absolute frequencies since these values depend on the voice family. User agents should map these values to appropriate frequencies based on the voice family and user environment. However, user agents must map these values in order (i.e., 'x-low' is a lower frequency than 'low', etc.). 'pitch-range' Value: | inherit Initial: 50 Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified Specifies variation in average pitch. The perceived pitch of a human voice is determined by the fundamental frequency and typically has a value of 120Hz for a male voice and 210Hz for a female voice. Human languages are spoken with varying inflection and pitch; these variations convey additional meaning and emphasis. Thus, a highly animated voice, i.e., one that is heavily inflected, displays a high pitch range. This property specifies the range over which these variations occur, i.e., how much the fundamental frequency may deviate from the average pitch. Values have the following meanings: A value between '0' and '100'. A pitch range of '0' produces a flat, monotonic voice. A pitch range of 50 produces normal inflection. Pitch ranges greater than 50 produce animated voices. 'stress' Value: | inherit Initial: 50 Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified Specifies the height of "local peaks" in the intonation contour of a voice. For example, English is a stressed language, and different parts of a sentence are assigned primary, secondary, or tertiary stress. The value of 'stress' controls the amount of inflection that results from these stress markers. This property is a companion to the 'pitch-range' property and is provided to allow developers to exploit higher-end auditory displays. Values have the following meanings: A value, between '0' and '100'. The meaning of values depends on the language being spoken. For example, a level of '50' for a standard, English-speaking male voice (average pitch = 122Hz), speaking with normal intonation and emphasis would have a different meaning than '50' for an Italian voice. 'richness' Value: | inherit Initial: 50 Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified Specifies the richness, or brightness, of the speaking voice. A rich voice will "carry" in a large room, a smooth voice will not. (The term "smooth" refers to how the wave form looks when drawn.) Values have the following meanings: A value between '0' and '100'. The higher the value, the more the voice will carry. A lower value will produce a soft, mellifluous voice. A.10 Speech properties: 'speak-punctuation' and 'speak-numeral' An additional speech property, 'speak-header', is described below. 'speak-punctuation' Value: code | none | inherit Initial: none Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified This property specifies how punctuation is spoken. Values have the following meanings: code Punctuation such as semicolons, braces, and so on are to be spoken literally. none Punctuation is not to be spoken, but instead rendered naturally as various pauses. 'speak-numeral' Value: digits | continuous | inherit Initial: continuous Applies to: all elements Inherited: yes Percentages: N/A Media: aural Computed value: as specified This property controls how numerals are spoken. Values have the following meanings: digits Speak the numeral as individual digits. Thus, "237" is spoken "Two Three Seven". continuous Speak the numeral as a full number. Thus, "237" is spoken "Two hundred thirty seven". Word representations are language-dependent. A.11 Audio rendering of tables When a table is spoken by a speech generator, the relation between the data cells and the header cells must be expressed in a different way than by horizontal and vertical alignment. Some speech browsers may allow a user to move around in the 2-dimensional space, thus giving them the opportunity to map out the spatially represented relations. When that is not possible, the style sheet must specify at which points the headers are spoken. A.11.1 Speaking headers: the 'speak-header' property 'speak-header' Value: once | always | inherit Initial: once Applies to: elements that have table header information Inherited: yes Percentages: N/A Media: aural Computed value: as specified This property specifies whether table headers are spoken before every cell, or only before a cell when that cell is associated with a different header than the previous cell. Values have the following meanings: once The header is spoken one time, before a series of cells. always The header is spoken before every pertinent cell. Each document language may have different mechanisms that allow authors to specify headers. For example, in HTML 4 ([HTML4]), it is possible to specify header information with three different attributes ("headers", "scope", and "axis"), and the specification gives an algorithm for determining header information when these attributes have not been specified. Image of a table created in MS Word [D] Image of a table with header cells ("San Jose" and "Seattle") that are not in the same column or row as the data they apply to. This HTML example presents the money spent on meals, hotels and transport in two locations (San Jose and Seattle) for successive days. Conceptually, you can think of the table in terms of an n-dimensional space. The headers of this space are: location, day, category and subtotal. Some cells define marks along an axis while others give money spent at points within this space. The markup for this table is: Travel Expense Report Meals Hotels Transport subtotal San Jose 25-Aug-97 37.74 112.00 45.00 26-Aug-97 27.28 112.00 45.00 subtotal 65.02 224.00 90.00 379.02 Seattle 27-Aug-97 96.25 109.00 36.00 28-Aug-97 35.00 109.00 36.00 subtotal 131.25 218.00 72.00 421.25 Totals 196.27 442.00 162.00 800.27 By providing the data model in this way, authors make it possible for speech enabled-browsers to explore the table in rich ways, e.g., each cell could be spoken as a list, repeating the applicable headers before each data cell: San Jose, 25-Aug-97, Meals: 37.74 San Jose, 25-Aug-97, Hotels: 112.00 San Jose, 25-Aug-97, Transport: 45.00 ... The browser could also speak the headers only when they change: San Jose, 25-Aug-97, Meals: 37.74 Hotels: 112.00 Transport: 45.00 26-Aug-97, Meals: 27.28 Hotels: 112.00 ... A.12 Sample style sheet for HTML This style sheet describes a possible rendering of HTML 4: @media aural { h1, h2, h3, h4, h5, h6 { voice-family: paul, male; stress: 20; richness: 90 } h1 { pitch: x-low; pitch-range: 90 } h2 { pitch: x-low; pitch-range: 80 } h3 { pitch: low; pitch-range: 70 } h4 { pitch: medium; pitch-range: 60 } h5 { pitch: medium; pitch-range: 50 } h6 { pitch: medium; pitch-range: 40 } li, dt, dd { pitch: medium; richness: 60 } dt { stress: 80 } pre, code, tt { pitch: medium; pitch-range: 0; stress: 0; richness: 80 } em { pitch: medium; pitch-range: 60; stress: 60; richness: 50 } strong { pitch: medium; pitch-range: 60; stress: 90; richness: 90 } dfn { pitch: high; pitch-range: 60; stress: 60 } s, strike { richness: 0 } i { pitch: medium; pitch-range: 60; stress: 60; richness: 50 } b { pitch: medium; pitch-range: 60; stress: 90; richness: 90 } u { richness: 0 } a:link { voice-family: harry, male } a:visited { voice-family: betty, female } a:active { voice-family: betty, female; pitch-range: 80; pitch: x-high } } A.13 Emacspeak For information, here is the list of properties implemented by Emacspeak, a speech subsystem for the Emacs editor. * voice-family * stress (but with a different range of values) * richness (but with a different range of values) * pitch (but with differently named values) * pitch-range (but with a different range of values) (We thank T. V. Raman for the information about implementation status of aural properties.) Appendix B. Bibliography Contents * B.1 Normative references * B.2 Informative references B.1 Normative references [COLORIMETRY] "Colorimetry", Third Edition, Commission Internationale de l'Eclairage, CIE Publication 15:2004, ISBN 3-901-906-33-9. Available at http://www.cie.co.at/publ/abst/15-2004.html [FLEX] "Flex: The Lexical Scanner Generator", Version 2.3.7, ISBN 1882114213. [HTML4] "HTML 4.01 Specification", D. Raggett, A. Le Hors, I. Jacobs, 24 December 1999. The latest version of the specification is available at http://www.w3.org/TR/html4/. The Recommendation defines three document type definitions: Strict, Transitional, and Frameset, all reachable from the Recommendation. [ICC42] Specification ICC.1:2004-10 (Profile version 4.2.0.0) Image technology colour management â Architecture, profile format, and data structure. Available at http://www.color.org/icc_specs2.html [ISO8879] "ISO 8879:1986(E): Information processing - Text and Office Systems - Standard Generalized Markup Language (SGML)", International Organization for Standardization (ISO), 15 October 1986. [ISO10646] "Information Technology - Universal Multiple- Octet Coded Character Set (UCS) - Part 1: Architecture and Basic Multilingual Plane", ISO/IEC 10646-1:2003. Useful roadmap of the BMP and plane 1 documents show which scripts sit at which numeric ranges. [PNG] "Portable Network Graphics (PNG) Specification (Second Edition)", David Duce, ed., 10 November 2003. Available at http://www.w3.org/TR/PNG/. [RFC3986] "Uniform Resource Identifier (URI): Generic Syntax," T. Berners-Lee, R. Fielding, L. Masinter, January 2005. Available at http://www.ietf.org/rfc/rfc3986. [RFC2045] "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", N. Freed and N. Borenstein, November 1996. Available at http://www.ietf.org/rfc/rfc2045.txt. Note that this RFC obsoletes RFC1521, RFC1522, and RFC1590. [RFC2616] "HTTP Version 1.1 ", R. Fielding, J. Gettys, J. Mogul, et al., June 1999. Available at http://www.ietf.org/rfc/rfc2616.txt. [RFC2119] "Key words for use in RFCs to Indicate Requirement Levels", S. Bradner, March 1997. Available at http://www.ietf.org/rfc/rfc2119.txt. [RFC2318] "The text/css Media Type", H. Lie, B. Bos, C. Lilley, March 1998. Available at http://www.ietf.org/rfc/rfc2318.txt. [SRGB] IEC 61966-2-1 (1999-10) - "Multimedia systems and equipment - Colour measurement and management - Part 2-1: Colour management - Default RGB colour space - sRGB, ISBN: 2-8318-4989-6 - ICS codes: 33.160.60, 37.080 - TC 100 - 51 pp. Available at http://domino.iec.ch/webstore/webstore.nsf/artnum/025408 [UAAG10] "User Agent Accessibility Guidelines 1.0." Ian Jacobs, Jon Gunderson, Eric Hansen (editors). 17 December 2002. Available at http://www.w3.org/TR/2002/REC-UAAG10-20021217 [UAX9] "Unicode Bidirectional Algorithm", Mark Davis. (Unicode Standard Annex #9.) 27 September 2010. Available at http://www.unicode.org/reports/tr9/ [UNICODE] The Unicode Consortium. The Unicode Standard, Version 6.0.0, (Mountain View, CA: The Unicode Consortium, 2011. ISBN 978-1-936213-01-6) and as updated from time to time by the publication of new versions. (See http://www.unicode.org/unicode/standard/versions/ for the latest version and additional information on versions of the standard and of the Unicode Character Database). Available at http://www.unicode.org/versions/Unicode6.0.0/ [XML10] "Extensible Markup Language (XML) 1.0 (fifth edition)" T. Bray, J. Paoli, C.M. Sperberg-McQueen, Eve Maler, François Yergeau, editors, 26 November 2008. Available at http://www.w3.org/TR/REC-xml/. [YACC] "YACC - Yet another compiler compiler", S. C. Johnson, Technical Report, Murray Hill, 1975. B.2 Informative references [CHARSETS] Registered charset values. Download a list of registered charset values from http://www.iana.org/assignments/character-sets. [CSS1] "Cascading Style Sheets, level 1", H. W. Lie and B. Bos, 17 December 1996, revised 11 January 1999 The latest version is available at http://www.w3.org/TR/CSS1 [CSS2] "Cascading Style Sheets, level 2, CSS2 Specification", B. Bos, H. W. Lie, C. Lilley and I. Jacobs, 12 May 1998 (revised 11 April 2008), http://www.w3.org/TR/2008/REC-CSS2-20080411/ [CSS3COLOR] "CSS3 Color Module," Tantek Ãelik, Chris Lilley, 28 October 2010, W3C Proposed Recommendation. Available at http://www.w3.org/TR/2010/PR-css3-color-20101028/ [CSS3LIST] "CSS3 module: lists," Tantek Ãelik, Ian Hickson, 7 November 2002, W3C working draft (work in progress). Available at http://www.w3.org/TR/2002/WD-css3-lists-20021107 [CSS3SEL] "Selectors", D. Glazman, T. Ãelik, I. Hickson, 15 December 2009 Available at http://www.w3.org/TR/2009/PR-css3-selectors-20091215/ [CSS3SPEECH] "CSS3 Speech Module", David Raggett, Daniel Glazman, Claudio Santambrogio, Daniel Weck, 19 April 2011, W3C Working Draft (work in progress). Available at http://www.w3.org/TR/2011/WD-css3-speech-20110419/ [DOM-LEVEL-3-CORE] "Document Object Model (DOM) Level 3 Core Specification", A. Le Hors, P. Le Hégaret, et al. (eds.), 7 April 2004, W3C Recommendation. Available at http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/. [MATH30] "Mathematical Markup Language (MathML) Version 3.0", D. Carlisle, P. Ion, R. Miner, 21 October 2010 Available at http://www.w3.org/TR/2010/REC-MathML3-20101021/ [MEDIAQ] "Media Queries", HÃ¥kon Wium Lie, Tantek Ãelik, Daniel Glazman, Anne van Kesteren, 27 July 2010 (Work in progress.) Available at http://www.w3.org/TR/2010/CR-css3-mediaqueries-20100727/ [P3P] "The Platform for Privacy Preferences 1.0 (P3P1.0) Specification", L. Cranor, M. Langheinrich, M. Marchiori, M. Presler-Marshall, J. Reagle, 16 April 2002 Available at http://www.w3.org/TR/2002/REC-P3P-20020416 [BCP47] "Tags for Identifying Languages", A. Phillips, M. Davis, September 2009. Available at http://www.rfc-editor.org/rfc/bcp/bcp47.txt. [SVG11] "Scalable Vector Graphics (SVG) 1.1 Specification", J. Ferraiolo, et.al. 14 January 2003 Available at http://www.w3.org/TR/2003/REC-SVG11-20030114 [WVAG20] "Web Content Accessibility Guidelines (WCAG) 2.0", Ben Caldwell, Michael Cooper, Loretta Guarino Reid, Gregg Vanderheiden, 11 December 2008. Available at: http://www.w3.org/TR/2008/REC-WCAG20-20081211/. [XHTML] "XHTML 1.0 The Extensible HyperText Markup Language", various authors, Available at: http://www.w3.org/TR/xhtml1/. [XMLID] "xml:id Version 1.0", J. Marsh, D. Veillard N. Walsh, 9 September 2005, W3C Recommendation. Available at: http://www.w3.org/TR/2005/REC-xml-id-20050909/. [XMLNAMESPACES] "Namespaces in XML 1.0 (third edition)", T. Bray, D. Hollander, A. Layman, R. Tobin, H. S. Thompson, 8 December 2009 Available at: http://www.w3.org/TR/2009/REC-xml-names-20091208/. Appendix C. Changes Contents * C.1 Additional property values + C.1.1 Section 4.3.6 Colors + C.1.2 Section 9.2.4 The 'display' property + C.1.3 Section 12.2 The 'content' property + C.1.4 Section 16.6 White space: the 'white-space' property + C.1.5 Section 18.1 Cursors: the 'cursor' property * C.2 Changes + C.2.1 Section 1.1 CSS 2.1 vs CSS 2 + C.2.2 Section 1.2 Reading the specification + C.2.3 Section 1.3 How the specification is organized + C.2.4 Section 1.4.2.1 Value + C.2.5 Section 1.4.2.6 Media groups + C.2.6 Section 1.4.2.7 Computed value + C.2.7 Section 1.4.4 Notes and examples + C.2.8 Section 1.5 Acknowledgments + C.2.9 Section 3.2 Conformance + C.2.10 Section 3.3 Error Conditions + C.2.11 Section 4.1.1 Tokenization + C.2.12 Section 4.1.3 Characters and case + C.2.13 Section 4.2 Rules for handling parsing errors + C.2.14 Section 4.3 Values + C.2.15 Section 4.3.2 Lengths + C.2.16 Section 4.3.4 URLs and URIs + C.2.17 Section 4.3.5 Counters + C.2.18 Section 4.3.6 Colors + C.2.19 Section 4.3.8 Unsupported Values + C.2.20 Section 4.4 CSS style sheet representation + C.2.21 Section 5.8.1 Matching attributes and attribute values + C.2.22 Section 5.8.3 Class selectors + C.2.23 Section 5.9 ID selectors + C.2.24 Section 5.10 Pseudo-elements and pseudo-classes + C.2.25 Section 5.11.2 The link pseudo-classes: :link and :visited + C.2.26 Section 5.11.4 The language pseudo-class: :lang + C.2.27 Section 5.12.1 The :first-line pseudo-element + C.2.28 Section 5.12.2 The :first-letter pseudo-element + C.2.29 Section 6.1 Specified, computed, and actual values + C.2.30 Section 6.4.1 Cascading order + C.2.31 Section 6.4.3 Calculating a selector's specificity + C.2.32 Section 6.4.4 Precedence of non-CSS presentational hints + C.2.33 Section 7.3 Recognized Media Types + C.2.34 Section 7.3.1 Media Groups + C.2.35 Section 8.3 Margin properties + C.2.36 Section 8.3.1 Collapsing margins + C.2.37 Section 8.4 Padding properties + C.2.38 Section 8.5.2 Border color + C.2.39 Section 8.5.3 Border style + C.2.40 Section 8.6 The box model for inline elements in bidirectional context + C.2.41 Section 9.1.2 Containing blocks + C.2.42 Section 9.2.1.1 Anonymous block boxes + C.2.43 Section 9.2.2.1 Anonymous inline boxes + C.2.44 Section 9.2.3 Run-in boxes + C.2.45 Section 9.2.4 The 'display' property + C.2.46 Section 9.3.1 Choosing a positioning scheme + C.2.47 Section 9.3.2 Box offsets + C.2.48 Section 9.4.1 Block formatting contexts + C.2.49 Section 9.4.2 Inline formatting context + C.2.50 Section 9.4.3 Relative positioning + C.2.51 Section 9.5 Floats + C.2.52 Section 9.5.1 Positioning the float + C.2.53 Section 9.5.2 Controlling flow next to floats + C.2.54 Section 9.7 Relationships between 'display', 'position', and 'float' + C.2.55 Section 9.9 Layered presentation + C.2.56 Section 9.10 Text direction + C.2.57 Chapter 10 Visual formatting model details + C.2.58 Section 10.1 Definition of "containing block" + C.2.59 Section 10.2 Content width + C.2.60 Section 10.3 Calculating widths and margins + C.2.61 Section 10.3.2 Inline, replaced elements + C.2.62 Section 10.3.3 Block-level, non-replaced elements in normal flow + C.2.63 Section 10.3.4 Block-level, replaced elements in normal flow + C.2.64 Section 10.3.5 Floating, non-replaced elements + C.2.65 Section 10.3.6 Floating, replaced elements + C.2.66 Section 10.3.7 Absolutely positioned, non-replaced elements + C.2.67 Section 10.3.8 Absolutely positioned, replaced elements + C.2.68 Section 10.4 Minimum and maximum widths + C.2.69 Section 10.5 Content height + C.2.70 Section 10.6 Calculating heights and margins + C.2.71 Section 10.6.1 Inline, non-replaced elements + C.2.72 Section 10.6.2 Inline replaced elements, block-level replaced elements in normal flow, 'inline-block' replaced elements in normal flow and floating replaced elements + C.2.73 Section 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' + C.2.74 Section 10.6.4 Absolutely positioned, non-replaced elements + C.2.75 Section 10.6.5 Absolutely positioned, replaced elements + C.2.76 Section 10.7 Minimum and maximum heights + C.2.77 Section 10.8 Line height calculations + C.2.78 Section 10.8.1 Leading and half-leading + C.2.79 Section 11.1 Overflow and clipping + C.2.80 Section 11.1.1 Overflow + C.2.81 Section 11.1.2 Clipping: the 'clip' property + C.2.82 Section 11.2 Visibility + C.2.83 Chapter 12 Generated content, automatic numbering, and lists + C.2.84 Section 12.1 The :before and :after pseudo-elements + C.2.85 Section 12.2 The 'content' property + C.2.86 Section 12.3.2 Inserting quotes with the 'content' property + C.2.87 Section 12.4 Automatic counters and numbering + C.2.88 Section 12.4.1 Nested counters and scope + C.2.89 Section 12.5 Lists + C.2.90 Section 12.5.1 Lists + C.2.91 Chapter 13 Paged media + C.2.92 Section 13.2.2 Page selectors + C.2.93 Section 13.3.1 Page break properties + C.2.94 Section 13.3.3 Allowed page breaks + C.2.95 Section 14.2.1 Background properties + C.2.96 Section 14.3 Gamma correction + C.2.97 Chapter 15 Fonts + C.2.98 Section 15.2 Font matching algorithm + C.2.99 Section 15.2.2 Font family + C.2.100 Section 15.5 Small-caps + C.2.101 Section 15.6 Font boldness + C.2.102 Section 15.7 Font size + C.2.103 Chapter 16 Text + C.2.104 Section 16.2 Alignment + C.2.105 Section 16.3.1 Underlining, over lining, striking, and blinking + C.2.106 Section 16.4 Letter and word spacing + C.2.107 Section 16.5 Capitalization + C.2.108 Section 16.6 White space + C.2.109 Chapter 17 Tables + C.2.110 Section 17.2 The CSS table model + C.2.111 Section 17.2.1 Anonymous table objects + C.2.112 Section 17.4 Tables in the visual formatting model + C.2.113 Section 17.4.1 Caption position and alignment + C.2.114 Section 17.5 Visual layout of table contents + C.2.115 Section 17.5.1 Table layers and transparency + C.2.116 Section 17.5.2.1 Fixed table layout + C.2.117 Section 17.5.2.2 Automatic table layout + C.2.118 Section 17.5.3 Table height algorithms + C.2.119 Section 17.5.4 Horizontal alignment in a column + C.2.120 Section 17.6 Borders + C.2.121 Section 17.6.1 The separated borders model + C.2.122 Section 17.6.1.1 Borders and Backgrounds around empty cells + C.2.123 Section 17.6.2 The collapsing border model + C.2.124 Section 17.6.2.1 Border conflict resolution + C.2.125 Section 18.1 Cursors: the 'cursor' property + C.2.126 Section 18.4 Dynamic outlines + C.2.127 Chapter 12 Generated content, automatic numbering, and lists + C.2.128 Appendix A. Aural style sheets + C.2.129 Appendix A Section 5 Pause properties + C.2.130 Appendix A Section 6 Cue properties + C.2.131 Appendix A Section 7 Mixing properties + C.2.132 Appendix B Bibliography + C.2.133 Other * C.3 Errors + C.3.1 Shorthand properties + C.3.2 Applies to + C.3.3 Section 4.1.1 (and G2) + C.3.4 Section 4.1.3 Characters and case + C.3.5 Section 4.3 (Double sign problem) + C.3.6 Section 4.3.2 Lengths + C.3.7 Section 4.3.3 Percentages + C.3.8 Section 4.3.4 URLs and URIs + C.3.9 Section 4.3.5 Counters + C.3.10 Section 4.3.6 Colors + C.3.11 Section 4.3.7 Strings + C.3.12 Section 5.10 Pseudo-elements and pseudo-classes + C.3.13 Section 6.4 The cascade + C.3.14 Section 8.1 Box Dimensions + C.3.15 Section 8.2 Example of margins, padding, and borders + C.3.16 Section 8.5.4 Border shorthand properties + C.3.17 Section 9.2.1 Block-level elements and block boxes + C.3.18 Section 9.3.1 Choosing a positioning scheme + C.3.19 Section 9.3.2 Box offsets + C.3.20 Section 9.4.1 Block formatting contexts + C.3.21 Section 9.4.2 Inline formatting context + C.3.22 Section 9.4.3 Relative positioning + C.3.23 Section 9.5 Floats + C.3.24 Section 9.5.1 Positioning the float + C.3.25 Section 9.5.2 Controlling flow next to floats + C.3.26 Section 9.6 Absolute positioning + C.3.27 Section 9.7 Relationships between 'display', 'position', and 'float' + C.3.28 Section 9.10 Text direction + C.3.29 Section 10.1 Definition of "containing block" + C.3.30 Section 10.3.3 Block-level, non-replaced elements in normal flow + C.3.31 Section 10.4 Minimum and maximum widths + C.3.32 Section 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' + C.3.33 Section 10.7 Minimum and maximum heights + C.3.34 Section 11.1.1 Overflow + C.3.35 Section 11.1.2 Clipping: the 'clip' property + C.3.36 Section 11.2 Visibility + C.3.37 Section 12.4.2 Counter styles + C.3.38 Section 12.6.2 Lists + C.3.39 Section 14.2 The background + C.3.40 Section 14.2.1 Background properties + C.3.41 Section 15.2 Font matching algorithm + C.3.42 Section 15.7 Font size + C.3.43 Section 16.1 Indentation + C.3.44 Section 16.2 Alignment + C.3.45 Section 17.2 The CSS table model + C.3.46 Section 17.2.1 Anonymous table objects + C.3.47 Section 17.4 Tables in the visual formatting model + C.3.48 Section 17.5 Visual layout of table contents + C.3.49 Section 17.5.1 Table layers and transparency + C.3.50 Section 17.6.1 The separated borders model + C.3.51 Section 18.2 System Colors + C.3.52 Section E.2 Painting order * C.4 Clarifications + C.4.1 Section 2.1 A brief CSS 2.1 tutorial for HTML + C.4.2 Section 2.2 A brief CSS 2.1 tutorial for XML + C.4.3 Section 2.3 The CSS 2.1 processing model + C.4.4 Section 3.1 Definitions + C.4.5 Section 4.1 Syntax + C.4.6 Section 4.1.1 Tokenization + C.4.7 Section 4.1.3 Characters and case + C.4.8 Section 4.1.7 Rule sets, declaration blocks, and selectors + C.4.9 Section 4.2 Rules for handling parsing errors + C.4.10 Section 4.3.1 Integers and real numbers + C.4.11 Section 4.3.2 Lengths + C.4.12 Section 4.3.4 URLs and URIs + C.4.13 Section 5.1 Pattern matching + C.4.14 Section 5.7 Adjacent sibling selectors + C.4.15 Section 5.8.1 Matching attributes and attribute values + C.4.16 Section 5.8.2 Default attribute values in DTDs + C.4.17 Section 5.9 ID selectors + C.4.18 Section 5.11.3 The dynamic pseudo-classes: :hover, :active, and :focus + C.4.19 Section 5.11.4 The language pseudo-class: :lang + C.4.20 Section 5.12.2 The :first-letter pseudo-element + C.4.21 Section 6.2 Inheritance + C.4.22 Section 6.2.1 The 'inherit' value + C.4.23 Section 6.3 The @import rule + C.4.24 Section 6.4 The Cascade + C.4.25 Section 6.4.1 Cascading order + C.4.26 Section 6.4.3 Calculating a selector's specificity + C.4.27 Section 7.2.1 The @media rule + C.4.28 Section 7.3 Recognized media types + C.4.29 Section 7.3.1 Media groups + C.4.30 Section 8.1 Box dimensions + C.4.31 Section 8.3 Margin properties + C.4.32 Section 8.3.1 Collapsing margins + C.4.33 Section 8.5.3 Border style + C.4.34 Section 9.1.1 The viewport + C.4.35 Section 9.2.4 The 'display' property + C.4.36 Section 9.3.1 Choosing a positioning scheme + C.4.37 Section 9.3.2 Box offsets + C.4.38 Section 9.4.2 Inline formatting context + C.4.39 Section 9.4.3 Relative positioning + C.4.40 Section 9.5 Floats + C.4.41 Section 9.5.1 Positioning the float + C.4.42 Section 9.5.2 Controlling flow next to floats + C.4.43 Section 9.8 Comparison of normal flow, floats, and absolute positioning + C.4.44 Section 10.1 Definition of "containing block" + C.4.45 Section 10.2 Content width + C.4.46 Section 10.3.3 Block-level, non-replaced elements in normal flow + C.4.47 Section 10.3.8 Absolutely positioning, replaced elements + C.4.48 Section 10.4 Minimum and maximum widths + C.4.49 Section 10.6 Calculating heights and margins + C.4.50 Section 10.7 Minimum and maximum heights + C.4.51 Section 10.8 Line height calculations + C.4.52 Section 10.8.1 Leading and half-leading + C.4.53 Section 11.1 Overflow and clipping + C.4.54 Section 11.1.1 Overflow + C.4.55 Section 11.1.2 Clipping + C.4.56 Section 11.2 Visibility + C.4.57 Section 12.1 The :before and :after pseudo-elements + C.4.58 Section 12.2 The 'content' property + C.4.59 Section 12.3.2 Inserting quotes with the 'content' property + C.4.60 Section 12.4 Automatic counters and numbering + C.4.61 Section 12.4.3 Counters in elements with 'display: none' + C.4.62 Section 14.2 The background + C.4.63 Section 15.1 Fonts Introduction + C.4.64 Section 15.2 Font matching algorithm + C.4.65 Section 15.2.2 Font family + C.4.66 Section 15.3.1 Generic font families + C.4.67 Section 15.4 Font styling + C.4.68 Section 15.5 Small-caps + C.4.69 Section 15.6 Font boldness + C.4.70 Section 15.7 Font size + C.4.71 Section 16.1 Indentation + C.4.72 Section 16.2 Alignment + C.4.73 Section 16.3.1 Underlining, over lining, striking, and blinking + C.4.74 Section 16.5 Capitalization + C.4.75 Section 16.6 White space + C.4.76 Section 17.1 Introduction to tables + C.4.77 Section 17.2 The CSS table model + C.4.78 Section 17.2.1 Anonymous table objects + C.4.79 Section 17.4 Tables in the visual formatting model + C.4.80 Section 17.5 Visual layout of table contents + C.4.81 Section 17.5.1 Table layers and transparency + C.4.82 Section 17.5.2 Table width algorithms + C.4.83 Section 17.5.2.1 Fixed table layout + C.4.84 Section 17.5.2.2 Automatic table layout + C.4.85 Section 17.5.4 Horizontal alignment in a column + C.4.86 Section 17.5.5 Dynamic row and column effects + C.4.87 Section 17.6.1 The separated borders model + C.4.88 Section 17.6.2 The collapsing borders model + C.4.89 Section 18.2 System Colors + C.4.90 Section 18.4 Dynamic outlines + C.4.91 Section 18.4.1 Outlines and the focus + C.4.92 Appendix D Default style sheet for HTML 4 * C.5 Errata since the Candidate Recommendation of July 2007 + C.5.1 Section 1.4.2.1 Value + C.5.2 Section 2.3 The CSS 2.1 processing model + C.5.3 Section 3.1 Definitions + C.5.4 Section 4.1.1 Tokenization + C.5.5 Section 4.1.2.2 Informative Historical Notes + C.5.6 Section 4.1.3 Characters and case + C.5.7 Section 4.1.3 Characters and case + C.5.8 Section 4.1.3 Characters and case + C.5.9 Section 4.1.3 Characters and case + C.5.10 Section 4.1.5 At-rules + C.5.11 Section 4.1.7 Rule sets, declaration blocks, and selectors + C.5.12 Section 4.2 Rules for handling parsing errors + C.5.13 Section 4.2 Rules for handling parsing errors + C.5.14 Section 4.3.2 Lengths + C.5.15 Section 4.3.5 Counters + C.5.16 Section 5.8.1 Matching attributes and attribute values + C.5.17 Section 5.8.2 Default attribute values in DTDs + C.5.18 Section 5.11.4 The language pseudo-class: :lang + C.5.19 Section 5.12.3 The :before and :after pseudo-elements + C.5.20 Section 6.3 The @import rule + C.5.21 Section 6.3 The @import rule + C.5.22 Section 6.4.1 Cascading order + C.5.23 Section 6.4.1 Cascading order + C.5.24 Section 7.2.1 The @media rule + C.5.25 Section 8.3.1 Collapsing margins + C.5.26 Section 8.3.1 Collapsing margins + C.5.27 Section 8.3.1 Collapsing margins + C.5.28 Section 9.2.2 Inline-level elements and inline boxes + C.5.29 Section 9.2.4 The 'display' property + C.5.30 Section 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' + C.5.31 Section 9.5 Floats + C.5.32 Section 9.5 Floats + C.5.33 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.5.34 Section 9.6.1 Fixed positioning + C.5.35 Section 9.9.1 Specifying the stack level: the 'z-index' property + C.5.36 Section 10.1 Definition of "containing block" + C.5.37 Section 10.3 Calculating widths and margins + C.5.38 Section 10.3.1 Inline, non-replaced elements + C.5.39 Section 10.3.2 Inline, replaced elements + C.5.40 Section 10.3.2 Inline, replaced elements + C.5.41 Section 10.3.3 Block-level, non-replaced elements in normal flow + C.5.42 Section 10.3.7 Absolutely positioned, non-replaced elements + C.5.43 Section 10.3.7 Absolutely positioned, non-replaced elements + C.5.44 Section 10.3.8 Absolutely positioned, replaced elements + C.5.45 Section 10.3.8 Absolutely positioned, replaced elements + C.5.46 Section 10.3.8 Absolutely positioned, replaced elements + C.5.47 Section 10.5 Content height: the 'height' property + C.5.48 Section 10.6.2 Inline replaced elements [â¦] + C.5.49 Section 10.6.4 Absolutely positioned, non-replaced elements + C.5.50 Section 10.6.5 Absolutely positioned, replaced elements + C.5.51 Section 10.8.1 Leading and half-leading + C.5.52 Section 11.1.1 Overflow: the 'overflow' property + C.5.53 Section 11.1.2 Clipping: the 'clip' property + C.5.54 Section 12.2 The 'content' property + C.5.55 Section 12.4.2 Counter styles + C.5.56 Section 12.5 Lists + C.5.57 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.5.58 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.5.59 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.5.60 Section 13.2 Page boxes: the @page rule + C.5.61 Section 13.2.1.1 Rendering page boxes that do not fit a target sheet + C.5.62 Section 13.2.3 Content outside the page box + C.5.63 Section 13.3.1 Page break properties: 'page-break-before', 'page-break-after', 'page-break-inside' + C.5.64 Section 13.3.1 Page break properties: 'page-break-before', 'page-break-after', 'page-break-inside' + C.5.65 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' + C.5.66 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' + C.5.67 Section 13.3.3 Allowed page breaks + C.5.68 Section 13.3.3 Allowed page breaks + C.5.69 Section 13.3.3 Allowed page breaks + C.5.70 Section 13.3.5 "Best" page breaks + C.5.71 Section 14.2 The background + C.5.72 Section 14.2 The background + C.5.73 Section 14.2.1 Background properties: 'background-color', 'background-image', 'background-repeat', 'background-attachment', 'background-position', and 'background' + C.5.74 Section 15.6 Font boldness: the 'font-weight' property + C.5.75 Section 16.6 Whitespace: the 'white-space' property + C.5.76 Section 16.6.1 The 'white-space' processing model + C.5.77 Section 17.2.1 Anonymous table objects + C.5.78 Section 17.2.1 Anonymous table objects + C.5.79 Section 17.4 Tables in the visual formatting model + C.5.80 Section 17.5.4 Horizontal alignment in a column + C.5.81 Section 18.1 Cursors: the 'cursor' property + C.5.82 Section B.2 Informative references + C.5.83 Appendix D. Default style sheet for HTML 4 + C.5.84 Appendix D. Default style sheet for HTML 4 + C.5.85 Section E.2 Painting order + C.5.86 Appendix G. Grammar of CSS 2.1 + C.5.87 Section G.1 Grammar + C.5.88 Section G.2 Lexical scanner + C.5.89 Section G.2 Lexical scanner + C.5.90 Section G.2 Lexical scanner + C.5.91 Section G.2 Lexical scanner + C.5.92 Appendix I. Index * C.6 Errata since the Candidate Recommendation of April 2009 + C.6.1 Section 4.2 Rules for handling parsing errors + C.6.2 Section 13.3.3 Allowed page breaks + C.6.3 Section 15.3 Font family: the 'font-family' property + C.6.4 Section 15.3.1.1 serif + C.6.5 Section 15.7 Font size: the 'font-size' property + C.6.6 Section 17.5.2.1 Fixed table layout + C.6.7 Section 17.5.3 Table height layout + C.6.8 Appendix G. Grammar of CSS 2.1 * C.7 Errata since the Candidate Recommendation of September 2009 + C.7.1 Section 1.4.2.1 Value + C.7.2 Section 3.1 Definitions + C.7.3 Section 4.1.1 Tokenization + C.7.4 Section 4.1.1 Tokenization + C.7.5 Section 4.1.1 Tokenization + C.7.6 Section 4.1.1 Tokenization + C.7.7 Section 4.1.2.2 Informative Historical Notes + C.7.8 Section 4.1.3 Characters and case + C.7.9 Section 4.1.3 Characters and case + C.7.10 Section 4.1.8 Declarations and properties + C.7.11 Section 4.2 Rules for handling parsing errors + C.7.12 Section 4.3.2 Lengths + C.7.13 Section 4.3.2 Lengths + C.7.14 Section 4.3.4 URLs and URIs + C.7.15 Section 4.3.4 URLs and URIs + C.7.16 Section 5.8.2 Default attribute values in DTDs + C.7.17 Section 5.11.4 The language pseudo-class: :lang + C.7.18 Section 5.12 Pseudo-elements + C.7.19 Section 5.12.1 The :first-line pseudo-element + C.7.20 Section 5.12.2 The :first-letter pseudo-element + C.7.21 Section 6.2 Inheritance + C.7.22 Section 6.4.4 Precedence of non-CSS presentational hints + C.7.23 Section 7.3 Recognized media types + C.7.24 Section 8.3.1 Collapsing margins + C.7.25 Section 8.3.1 Collapsing margins + C.7.26 Section 9.2.1 Block-level elements and block boxes + C.7.27 Section 9.2.1.1 Anonymous block boxes + C.7.28 Section 9.2.1.1 Anonymous block boxes + C.7.29 Section 9.2.1.1 Anonymous block boxes + C.7.30 Section 9.2.1.1 Anonymous block boxes + C.7.31 Section 9.2.2 Inline-level elements and inline boxes + C.7.32 Section 9.2.3 Run-in boxes + C.7.33 Section 9.2.4 The 'display' property + C.7.34 Section 9.2.4 The 'display' property + C.7.35 Section 9.3 Positioning schemes + C.7.36 Section 9.4 Normal flow + C.7.37 Section 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' + C.7.38 Section 9.5 Floats + C.7.39 Section 9.5 Floats + C.7.40 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.7.41 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.7.42 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.7.43 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.7.44 Section 14.2.1 Background properties + C.7.45 Section 9.9.1 Specifying the stack level: the 'z-index' property + C.7.46 Section 9.10 Text direction: the 'direction' and 'unicode-bidi' properties + C.7.47 Section 9.10 Text direction: the 'direction' and 'unicode-bidi' properties + C.7.48 Section 9.10 Text direction: the 'direction' and 'unicode-bidi' properties + C.7.49 Section 10.1 Definition of "containing block" + C.7.50 Section 10.2 Content width: the 'width' property + C.7.51 Section 10.2 Content width: the 'width' property + C.7.52 Section 10.2 Content width: the 'width' property + C.7.53 Section 10.5 Content height: the 'height' property + C.7.54 Section 10.5 Content height: the 'height' property + C.7.55 Section 10.6.7 'Auto' heights for block formatting context roots + C.7.56 Section 10.7 Minimum and maximum heights: 'min-height' and 'max-height' + C.7.57 Section 10.8 Line height calculations: the 'line-height' and 'vertical-align' properties + C.7.58 Section 10.8 Line height calculations: the 'line-height' and 'vertical-align' properties + C.7.59 Section 10.8.1 Leading and half-leading + C.7.60 Section 10.8.1 Leading and half-leading + C.7.61 Section 10.8.1 Leading and half-leading + C.7.62 Section 11.1 Overflow and clipping + C.7.63 Section 11.1.1 Overflow: the 'overflow' property + C.7.64 Section 11.1.1 Overflow: the 'overflow' property + C.7.65 Section 11.1.1 Overflow: the 'overflow' property + C.7.66 Section 11.1.2 Clipping: the 'clip' property + C.7.67 Section 12.5 Lists + C.7.68 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.7.69 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.7.70 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.7.71 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.7.72 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.7.73 Section 13.2 Page boxes: the @page rule + C.7.74 Section 13.2.2 Page selectors: selecting left, right, and first pages + C.7.75 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' + C.7.76 Section 13.3.3 Allowed page breaks + C.7.77 Section 15.3 Font family: the 'font-family' property + C.7.78 Section 15.3.1 Generic font families + C.7.79 Section 15.6 Font boldness: the 'font-weight' property + C.7.80 Section 15.6 Font boldness: the 'font-weight' property + C.7.81 Section 15.7 Font size: the 'font-size' property + C.7.82 Section 16.1 Indentation: the 'text-indent' property + C.7.83 Section 16.1 Indentation: the 'text-indent' property + C.7.84 Section 16.2 Alignment: the 'text-align' property + C.7.85 Section 16.2 Alignment: the 'text-align' property + C.7.86 Section 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property + C.7.87 Section 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property + C.7.88 Section 16.4 Letter and word spacing: the 'letter-spacing' and 'word-spacing' properties + C.7.89 Section 16.6 White space: the 'white-space' property + C.7.90 Section 16.6.1 The 'white-space' processing model + C.7.91 Section 16.6.1 The 'white-space' processing model + C.7.92 Section 16.6.1 The 'white-space' processing model + C.7.93 Section 17.2 The CSS table model + C.7.94 Section 17.2.1 Anonymous table objects + C.7.95 Section 17.2.1 Anonymous table objects + C.7.96 Section 17.4 Tables in the visual formatting model + C.7.97 Section 17.4 Tables in the visual formatting model + C.7.98 Section 17.5.2.2 Automatic table layout + C.7.99 Section 17.5.3 Table height algorithms + C.7.100 Section 17.5.4 Horizontal alignment in a column + C.7.101 Section B.2 Informative references + C.7.102 Section D. Default style sheet for HTML 4 + C.7.103 Section E.2 Painting order + C.7.104 Appendix G Grammar of CSS 2.1 * C.8 Changes since the working draft of 7 December 2010 + C.8.1 8.3.1 Collapsing margins + C.8.2 10.8.1 Leading and half-leading + C.8.3 10.3 Calculating widths and margins + C.8.4 14.3 Gamma correction + C.8.5 11.1.2 Clipping: the 'clip' property + C.8.6 9.4.2 Inline formatting contexts + C.8.7 10.3.2 Inline, replaced elements + C.8.8 10.1 Definition of "containing block" + C.8.9 13.2.2 Page selectors: selecting left, right, and first pages + C.8.10 8.3.1 Collapsing margins + C.8.11 10.8 Line height calculations: the 'line-height' and 'vertical-align' properties + C.8.12 10.8.1 Leading and half-leading + C.8.13 10.6.1 Inline, non-replaced elements + C.8.14 9.5.1 Positioning the float: the 'float' property + C.8.15 9.2.1.1 Anonymous block boxes + C.8.16 5.12.1 The :first-line pseudo-element + C.8.17 16.6 White space: the 'white-space' property + C.8.18 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.8.19 9.7 Relationships between 'display', 'position', and 'float' + C.8.20 9.4.2 Inline formatting contexts + C.8.21 4.1.9 Comments + C.8.22 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties + C.8.23 9.5.1 Positioning the float: the 'float' property + C.8.24 9.3 Positioning schemes + C.8.25 9.10 Text direction: the 'direction' and 'unicode-bidi' properties + C.8.26 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property + C.8.27 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property + C.8.28 10.4 Minimum and maximum widths: 'min-width' and 'max-width' + C.8.29 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' + C.8.30 9.2.1.1 Anonymous block boxes + C.8.31 17.4 Tables in the visual formatting model + C.8.32 11.1.2 Clipping: the 'clip' property + C.8.33 13.2 Page boxes: the @page rule + C.8.34 4.1.1 Tokenization + C.8.35 4.2 Rules for handling parsing errors + C.8.36 3.1 Definitions + C.8.37 4.3.4 URLs and URIs + C.8.38 9.5 Floats + C.8.39 11.1.1 Overflow: the 'overflow' property + C.8.40 9.2.1.1 Anonymous block boxes + C.8.41 16.2 Alignment: the 'text-align' property + C.8.42 9.5 Floats + C.8.43 9.4.2 Inline formatting contexts + C.8.44 5.12 Pseudo-elements + C.8.45 9.5 Floats + C.8.46 9.5 Floats + C.8.47 14.2.1 Background properties: 'background-color', 'background-image', 'background-repeat', 'background-attachment', 'background-position', and 'background' + C.8.48 9.2.4 The 'display' property + C.8.49 6.1.2 Computed values + C.8.50 10.3.2 Inline, replaced elements + C.8.51 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.8.52 G.2 Lexical scanner + C.8.53 Section 9.5.2 Controlling flow next to floats: the 'clear' property + C.8.54 9.5 Floats + C.8.55 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' This appendix is informative, not normative. CSS 2.1 is an updated revision of CSS2. The changes between the CSS2 specification (see [CSS2]) and this specification fall into five groups: known errors, typographical errors, clarifications, changes and additions. Typographical errors are not listed here. In addition, this chapter lists the errata (part 1 and part 2) that were subsequently applied to CSS 2.1 since it became a Candidate Recommendation in July 2007. This chapter is not a complete list of changes. Minor editorial changes and most changes to examples are also not listed here. C.1 Additional property values C.1.1 Section 4.3.6 Colors New color value: 'orange' C.1.2 Section 9.2.4 The 'display' property New 'display' value: 'inline-block' C.1.3 Section 12.2 The 'content' property New 'content' values 'none' and 'normal'. (The values 'none' and 'normal' are equivalent in CSS 2.1, but may have different functions in CSS3.) C.1.4 Section 16.6 White space: the 'white-space' property New 'white-space' values: 'pre-wrap' and 'pre-line' C.1.5 Section 18.1 Cursors: the 'cursor' property New 'cursor' value: 'progress' C.2 Changes C.2.1 Section 1.1 CSS 2.1 vs CSS 2 This new section is added to explain the motivation for CSS2.1 and its relation to CSS2. C.2.2 Section 1.2 Reading the specification This section (formerly Section 1.1) has been marked non-normative. C.2.3 Section 1.3 How the specification is organized This section (formerly Section 1.2) has been marked non-normative. C.2.4 Section 1.4.2.1 Value This section (formerly unnumbered under 1.3.2) notes that value types are specified in terms of tokens and that spaces may appear between tokens in values. A note explains that spaces are required between some tokens. C.2.5 Section 1.4.2.6 Media groups This section (formerly unnumbered under 1.3.2) now declares the Media line in property definitions to be non-normative. C.2.6 Section 1.4.2.7 Computed value A new line is added to each property definition specifying what the computed values are for the property. (This defines what level of computation is done to a property value before inheritance and before certain other calculations.) C.2.7 Section 1.4.4 Notes and examples This section (formerly 1.3.4) now specifies that HTML examples lacking DOCTYPE declarations are SGML Text Entities conforming to the HTML 4.01 Strict DTD [HTML4]. The markup for many examples has been reformulated to either include a DOCTYPE or conform to this definition. C.2.8 Section 1.5 Acknowledgments This section (formerly 1.4) has been updated to reflect contributions to CSS2.1 and has been marked non-normative. C.2.9 Section 3.2 Conformance Support for user style sheets is now required (in most cases), rather than just recommended. Support for turning of author style sheets is now required. Application of CSS properties to form controls is explicitly undefined. Authors are recommended to treat form control styling capabilities in UAs as experimental. C.2.10 Section 3.3 Error Conditions This section changed to say that error handling is specified in most cases. C.2.11 Section 4.1.1 Tokenization Added INVALID token and rules for its definition. An optional hyphen, "-", is now allowed at the beginning of an "ident" for vendor extensions. (See section 4.1.2.1) The underscore character ("_") is allowed in identifiers. The definitions of the lexical macros "nmstart" and "nmchar" now include it. See also section 4.1.2.1 (Vendor extensions). The "escape" macro has been modified to allow the escaping of any character except newlines, form feeds, and hex digits (to avoid conflict with Unicode escapes). Modified "string1" and "string2" macros by defining allowed characters through excluding disallowed characters. This allows invisible ASCII characters to be included in a string. C.2.12 Section 4.1.3 Characters and case Updated prose about identifiers (second bullet point) to match changes in the tokenization (above). Excluded null (0x0) character from CSS numerical escapes and indicate that it is undefined in CSS2.1 what happens if such a character is encountered. Allowed the use of U+FFFD as a replacement for characters outside the range allowed by Unicode. CSS is no longer case-insensitive, but case-sensitive with exceptions. Changed "All CSS style sheets are case-insensitive, except for parts that are not under the control of CSS" to "All CSS syntax is case-insensitive within the ASCII range (i.e., [a-z] and [A-Z] are equivalent), except for parts that are not under the control of CSS." See also the change to case-sensitivity of counters in 4.3.5. C.2.13 Section 4.2 Rules for handling parsing errors Defined parsing in the cases of Malformed Declarations, Unexpected End of Stylesheet, and Unexpected End of String. C.2.14 Section 4.3 Values Sections 4.3.7 (Angles), 4.3.8 (Times), and 4.3.9 (Frequencies) have been moved to the informative Appendix A. C.2.15 Section 4.3.2 Lengths Added a paragraph on heuristics for finding the x-height of a font. C.2.16 Section 4.3.4 URLs and URIs Updated URI references to RFC3986. C.2.17 Section 4.3.5 Counters Changed "Counters are denoted by identifiers" to "Counters are denoted by [INS: case-sensitive :INS] identifiers" (see also the change to case-sensitivity in 4.1.3). C.2.18 Section 4.3.6 Colors Defined the numeric values corresponding to color keywords instead of referencing HTML4 for those values. UAs are now allowed to intelligently map colors outside the gamut into the gamut instead of simply clipping them into the range of the gamut. C.2.19 Section 4.3.8 Unsupported Values Added this section to recommend that unsupported properties and values be ignored as if they were invalid. C.2.20 Section 4.4 CSS style sheet representation Changed character encoding detection rule 2 to include a BOM and referred to additional rules below. Added rule 4 to provide for use of the referring style sheet or document's character encoding. Added rule 5 to require falling back to UTF-8. Removed the restriction on using @charset in embedded style sheets. Allowed a BOM to precede the @charset rule. Added requirement that @charset rule must be a literal '@charset"...";', not a CSS-syntax equivalent. Added requirement to support for UTF-8 at minimum. Specified that any @charset rule not at the beginning of the style sheet must be ignored. Removed note on theoretical problem with @charset problem and precisely defined rules for character encoding detection based on @charset and/or BOM. Specified that UAs must ignore style sheets in unknown encodings. C.2.21 Section 5.8.1 Matching attributes and attribute values BCP 47 replaces RFC 1766. C.2.22 Section 5.8.3 Class selectors Class selectors are allowed for other formats than HTML. Added a note about matching classes in formats with multiple class attributes per element. The behavior is non-normative, because, at the time of writing, there exist no such formats. C.2.23 Section 5.9 ID selectors Specified how to match elements with two or more ID attributes. C.2.24 Section 5.10 Pseudo-elements and pseudo-classes Removed exception for HTML UAs that allowed them (and only them) to ignore ':first-letter' and ':first-line'. C.2.25 Section 5.11.2 The link pseudo-classes: :link and :visited UAs may return a :visited link to :link status at some point. (This was previously a note, but is now normative.) Added a note about privacy concerns with link pseudo classes and allowed UAs to treat :visited as :link. C.2.26 Section 5.11.4 The language pseudo-class: :lang The identifier C in ':lang(C)' need not be a valid language code, but it must not be empty. C.2.27 Section 5.12.1 The :first-line pseudo-element ':first-line' also applies to inline blocks, table captions and table cells. Added a definition of "first formatted line" to make the rules about which line is the first line more precise. UAs are no longer forbidden from applying more properties than the given list. C.2.28 Section 5.12.2 The :first-letter pseudo-element More precise definition of first letter. Added rules for cases where the first letter is in an inline block or table cell. Added rules for cases when preceding punctuation is in a different element from the first letter itself. UAs may apply other properties to first letters than the given list. Unicode character classes Pi and Pf added to the definition of punctuation. C.2.29 Section 6.1 Specified, computed, and actual values Redefined "computed value" and created the concept of "used value" so that inheritance can be performed without laying out the document. This change has the effect of allowing (requiring) percentages to be inherited as percentages and affects many other layout calculations throughout the spec. Since computed value of a property can now also be a percentage. In particular, the following properties now inherit the percentage if the specified value is a percentage: * background-position * bottom, left, right, top * height, width * margin-bottom, margin-left, margin-right, margin-top, * min-height, min-width * padding-bottom, padding-left, padding-right, padding-top * text-indent Note that only 'text-indent' inherits by default, the others only inherit if the 'inherit' keyword is specified. C.2.30 Section 6.4.1 Cascading order Changed suggestion that user be able to turn off author styles to a requirement. C.2.31 Section 6.4.3 Calculating a selector's specificity The "style" attribute now has a higher specificity than any style rule. Pseudo-elements are now counted with elements in calculating a a selector's specificity. C.2.32 Section 6.4.4 Precedence of non-CSS presentational hints "Non-CSS presentational hints" no longer exist, with the exception of a small set of attributes in HTML. C.2.33 Section 7.3 Recognized Media Types Added 'speech' media type. Marked "Media" field in property descriptions informative. C.2.34 Section 7.3.1 Media Groups Marked this section informative. Added sound to 'handheld' in media type/media group table. Changed 'tactile' to be both 'static' and 'interactive'. C.2.35 Section 8.3 Margin properties If the containing block's width depends on an element with percentage margins, then the resulting layout is undefined in CSS 2.1. C.2.36 Section 8.3.1 Collapsing margins In the definition of "collapsing margins", added "non-empty content" and "clearance" to the parenthetical list of things that prevent consecutive margins from being adjoining. Vertical margins of elements with 'overflow' other than 'visible' no longer collapse with their in-flow children. Defined how margins collapse through an element with adjoining top and bottom margins. Added that margins of the root element's box do not collapse. More rigorously defined "adjoining" for margin collapsing. Sixth bullet, second sub-bullet: to find the position of the top border edge, assume the element has a bottom (rather than top) border. Margins of relatively positioned elements do sometimes collapse. C.2.37 Section 8.4 Padding properties If the containing block's width depends on an element with percentage padding, then the resulting layout is undefined in CSS 2.1. C.2.38 Section 8.5.2 Border color 'transparent' can now be specified independently for each border side, on par with . C.2.39 Section 8.5.3 Border style 3D border styles ('groove', 'ridge', 'inset', 'outset') now depend on the corresponding border-color rather than on 'color'. C.2.40 Section 8.6 The box model for inline elements in bidirectional context Added this new section to specify layout of inline boxes when affected by bidi. C.2.41 Section 9.1.2 Containing blocks Removed paragraphs about the initial containing block, as this is now defined differently. (See changes to section 10.1.) C.2.42 Section 9.2.1.1 Anonymous block boxes Added a paragraph to define formatting when an inline box contains a block box. Specified what property values are applied to anonymous boxes. C.2.43 Section 9.2.2.1 Anonymous inline boxes Specified that collapsed white space does not generate anonymous inline boxes. C.2.44 Section 9.2.3 Run-in boxes Changed run-in rules so that a) run-ins that contain blocks become blocks b) run-ins can only run into sibling blocks and c) run-ins cannot run into other run-ins. C.2.45 Section 9.2.4 The 'display' property The 'marker' and 'compact' values of the 'display' property are not part of CSS 2.1. Text relating to these values has been removed throughout the specification. Defined the computed value of 'display' as the specified value except for positioned and floating elements and for the root element. The computed value of 'display' for these elements is defined in section 9.7 and is slightly different from the definition in CSS2. Conforming HTML UAs are no longer allowed to ignore the 'display' property. C.2.46 Section 9.3.1 Choosing a positioning scheme The 'position' property now applies to all elements, including generated content. The effect of relative positioning on table captions and internal table elements is undefined in CSS 2.1. For fixed positioning, introduced a conflict between this section and section 10.1 rule 3. See howcome [member-only] for rationale. Forbid UAs from paginating the content of fixed boxes. UAs are allowed to treat all values of 'position' as 'static' on the root element. C.2.47 Section 9.3.2 Box offsets Defined computed values of 'top', 'right', 'bottom', 'left' based on the value of 'position'. Percentage offsets are no longer undefined for containing blocks without an explicit height. C.2.48 Section 9.4.1 Block formatting contexts Specified that floats, absolutely positioned elements, inline-blocks, table-cells, table-captions, and elements with 'overflow' other than 'visible' establish new block formatting contexts. In the paragraph about the position of a box's outer edge with respect to its containing block, except boxes that establish a new block formatting context, as they may become narrower due to floats. C.2.49 Section 9.4.2 Inline formatting context Specified that the effect of 'justify' on the content of a line box does not affect the contents of inline-table and inline-block boxes. Empty line boxes are now required to be treated as zero-height and ignored in margin collapsing. C.2.50 Section 9.4.3 Relative positioning Added several paragraphs and an example to explain exactly what the computed values of relatively-positioned offsets are, how they affect each other, and what happens when the positioning is overconstrained. (These were not previously defined.) C.2.51 Section 9.5 Floats Floats are no longer required to have an explicit width. Floats outside of line boxes no longer align to the bottom of the preceding block box; it is implied that they are initially aligned with their non-floated position. Specified that "If a shortened line box is too small to contain any further content, then it is shifted downward until either it fits or there are no more floats present." Specified that the border box of a table, block-level replaced element, or element in the normal flow that establishes a new block formatting context must not overlap any floats in the same block formatting context. C.2.52 Section 9.5.1 Positioning the float The 'float' property now also applies to :before/:after and generated content. UAs are now allowed to treat all values of float as 'none' on the root element. Added to rule 4 prose to define the position of a float when it occurs between two collapsing margins. C.2.53 Section 9.5.2 Controlling flow next to floats Defined clearance to precisely detail the 'clear' property's effect on margin collapsing and the block's cleared position. Added note to explain effect of 'clear' on inline elements since CSS1 (but not CSS2 or CSS 2.1) allows 'clear' on inline elements. C.2.54 Section 9.7 Relationships between 'display', 'position', and 'float' Changed rules to convert 'display' not always to 'block', but to an appropriate block-level display value as given by a mapping table. Added rule 4 to convert root element's 'display' value according to the mapping. C.2.55 Section 9.9 Layered presentation Specified that the background and borders of an element that forms a stacking context are behind all of its descendants, altered stacking context prose to be more precise, and added a normative Appendix E: Elaborate description of Stacking Contexts to be even more precise about the position of borders, backgrounds, and content on the z-axis. C.2.56 Section 9.10 Text direction Conforming UAs are now allowed to not support bidirectional text; in this case they must ignore the 'direction' and 'unicode-bidi' properties. However since applying bidi can have an effect even when a document does not contain right-to-left characters, UAs that do support bidi are no longer permitted to not apply the algorithm just because the document lacks right-to-left characters. Added a paragraph to define precisely how the Unicode bidirectional algorithm applies to text in the CSS formatting model and how the CSS 'direction' property on blocks maps into the algorithm. Conforming HTML UAs are no longer exempt from supporting 'direction' and 'unicode-bidi'. C.2.57 Chapter 10 Visual formatting model details Updated prose to use the terms "specified", "computed" and "used" as appropriate when referencing values. This affects many calculations in this section. (See changes to section 6.1.) C.2.58 Section 10.1 Definition of "containing block" In rule 1, defined the initial containing block as the viewport for continuous media and the page area for paged media. (It was previously undefined.) In rule 2, defined the page area as the containing block for fixed positioned elements in paged media. In rule 4.1, when the containing block of an absolutely-positioned element is formed by an inline-level element, it is now formed by that element's padding edges, not its content edges. In rule 4, changed the containing block for absolutely positioned elements with only statically positioned elements from the root's content box to the initial containing block. Specified the positioning and breaking behavior of absolutely-positioned elements in paged media. C.2.59 Section 10.2 Content width Declared that if the containing block's width depends on an element's percentage width, then the resulting layout is undefined in CSS 2.1. C.2.60 Section 10.3 Calculating widths and margins The computed values of 'left' and 'right' for are now defined in section 9.3.2. The value 'auto' does not always compute to zero. Added sections 10.3.9 and 10.3.10 to define calculations for inline blocks. C.2.61 Section 10.3.2 Inline, replaced elements The sizing algorithm for replaced elements now takes into account and attempts to preserve the replaced content's intrinsic ratio. Sizing of replaced elements with percentage intrinsic sizes and without intrinsic sizes is now also defined. The effect of percentage intrinsic widths is now undefined for CSS level 2, rather than ignored. C.2.62 Section 10.3.3 Block-level, non-replaced elements in normal flow Specified that a computed total of the width, padding, and borders that is greater than the containing block width causes auto margins to be treated as zero in the rest of the rules. This avoids 'auto' margins being negative on the start edge. C.2.63 Section 10.3.4 Block-level, replaced elements in normal flow Applied changes to section 10.3.2 and section 10.3.3 to block-level replaced elements in normal flow by referring to the calculations in those sections. C.2.64 Section 10.3.5 Floating, non-replaced elements Defined computations for 'auto' width floats as shrink-to-fit. (Floats were previously required to have fixed widths.) C.2.65 Section 10.3.6 Floating, replaced elements Applied changes to section 10.3.2 to this section by referencing it for 'auto' width calculations. C.2.66 Section 10.3.7 Absolutely positioned, non-replaced elements Defined the static position of an element more precisely. Rewrote constraint rules. The 'direction' property of the containing block of the static position determines which side is clamped to the static position, not the 'direction' property of the containing block of the absolutely positioned element. C.2.67 Section 10.3.8 Absolutely positioned, replaced elements In rule 1, applied sizing rules from section 10.3.2. In rule 2 (formerly rules 2 and 3), referred to new definition of 'static position' in section 10.3.7. Also in rule 2, the 'direction' property of the containing block of the static position determines which side is clamped to the static position, not the 'direction' property of the containing block of the absolutely positioned element. In rule 4 (formerly rule 5), prevented 'auto' left and right margins in resulting in a negative margin on the start edge. C.2.68 Section 10.4 Minimum and maximum widths Specified that if the containing block's width is negative, the used value of a percentage min/max width is zero. Specified that if the min/max width is specified in percentages and the containing block's width depends on this element's width, then the resulting layout is undefined in CSS 2.1. The UA is no longer allowed to select an arbitrary minimum width. The used width of replaced elements with an intrinsic ratio and both 'width' and 'height' specified as 'auto' is now calculated according to a table designed to preserve the intrinsic ratio as much as possible within the given constraints. C.2.69 Section 10.5 Content height Removed mention of 'line-height' for inline elements since their content box height no longer depends on 'line-height'. Percentage heights on absolutely-positioned elements are no longer treated as 'auto' when the containing block's height is not explicitly specified. Added a note to explain why this is possible. Specified that a percentage height on the root element is relative to the initial containing block. C.2.70 Section 10.6 Calculating heights and margins The computed values of 'top' and 'bottom' for are now defined in section 9.3.2. The value 'auto' does not always compute to zero. Added section 10.6.6 to cover cases that are no longer covered under the previous sections. Added section 10.6.7 to define 'auto' heights for block formatting context roots. (Unlike other block boxes, the height of these boxes increases to accommodate any normal-flow descendant floats.) C.2.71 Section 10.6.1 Inline, non-replaced elements The height of an inline box is no longer given by the 'line-height' property and is now undefined. This section now suggests that the height of the box can be based on the font. C.2.72 Section 10.6.2 Inline replaced elements, block-level replaced elements in normal flow, 'inline-block' replaced elements in normal flow and floating replaced elements The sizing algorithm for replaced elements now takes into account and attempts to preserve the replaced content's intrinsic ratio. Sizing of replaced elements with percentage intrinsic sizes and without intrinsic sizes is now also defined. Specified that for inline elements, the margin box is used when calculating the height of the line box. C.2.73 Section 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' This section now only applies to elements whose 'overflow' value computes to 'visible'; elements with other values of 'overflow' are discussed in the new section 10.6.7 ('Auto' heights for block formatting context roots). C.2.74 Section 10.6.4 Absolutely positioned, non-replaced elements Defined the static position of an element more precisely. Rewrote constraint rules. C.2.75 Section 10.6.5 Absolutely positioned, replaced elements In rule 1, applied sizing rules from section 10.6.2. C.2.76 Section 10.7 Minimum and maximum heights Percentage min/max heights on absolutely-positioned elements are no longer treated as '0'/'none' when the containing block's height is not explicitly specified. However if the containing block's width depends on an element's percentage width, then the resulting layout is undefined in CSS 2.1. The used width of replaced elements with an intrinsic ratio and both 'width' and 'height' specified as 'auto' is now calculated according to a table designed to preserve the intrinsic ratio as much as possible within the given constraints. C.2.77 Section 10.8 Line height calculations Added rule 4 to specify that the height of the line box must be at least as much as that specified by the 'line-height' property on the this block. C.2.78 Section 10.8.1 Leading and half-leading UAs are no longer permitted to clip content to the line box, and are instead asked to render overlapping boxes in document order. 'line-height' set on a block no longer specifies the minimal height of each inline box; instead it specifies the minimal height of each line box. The exact effect of this requirement is expressed in terms of struts; it is affected by vertical-alignment. Adjusted text to reflect that the content box height of an inline is no longer dictated by the 'line-height' property. Since the content box is now defined by the font and not by the line-height, 'text-top' and 'text-bottom' refer to the content area instead of the font. Defined 'top' and 'bottom' alignment in terms of aligned subtrees to take into account any protruding descendants. Defined the baseline of inline tables and inline blocks. C.2.79 Section 11.1 Overflow and clipping Specified that 'overflow' clips to the padding edge. C.2.80 Section 11.1.1 Overflow 'projection' media are no longer permitted to print overflowing content for 'overflow: scroll'. 'Print' media now may, as opposed to should. UAs are now required to apply the 'overflow' property set on the root element to the viewport. Additionally, HTML UAs must use the 'overflow' property on the HTML BODY element instead if the root element's 'overflow' value is 'visible'. Specified placement of scrollbar in the box model. The width of any scrollbars is no longer included in the width of the containing block. (And consequently, all text in section 10.3 that subtracts the scrollbar width from the containing block width has been removed.) C.2.81 Section 11.1.2 Clipping: the 'clip' property The 'clip' property now applies only to absolutely positioned elements. Furthermore, it applies to those elements even when their 'overflow' is 'visible'. The default value of 'clip', 'auto', now indicates no clipping rather than clipping to the element's border box. Values of "rect()" should be separated by commas. UAs are required to support this syntax, but may also support a space-separated syntax since CSS2 was not clear about this. While CSS2 specified that values of "rect()" give offsets from the respective sides of the box, current implementations interpret values with respect to the top and left edges for all four values (top, right, bottom, and left). This is now the specified interpretation. C.2.82 Section 11.2 Visibility The 'visibility' property is now defined to inherit, and descendant elements can override an ancestor's hidden visibility. C.2.83 Chapter 12 Generated content, automatic numbering, and lists Moved all discussion of aural rendering to Appendix A. C.2.84 Section 12.1 The :before and :after pseudo-elements Removed restrictions on which properties and property values are allowed on ':before' and ':after' pseudo-elements. C.2.85 Section 12.2 The 'content' property The initial value of 'content' is now 'normal', not the empty string. The 'content' property now distinguishes between the empty string, which creates an empty box; and 'normal'/'none', which create no box at all. (There is no distinction between 'normal' and 'none' in level 2.) A UA is now allowed to report a URI that fails to download. Removed recommendation to authors to put rules with media-sensitive 'content' properties inside '@media'. Whether '\A' escapes in generated content create line breaks is now subject to the 'white-space' property. The former section 12.3 on interaction between ':before', ':after' and elements with 'display: compact' or 'display: run-in' has been removed. (The interaction is already fully defined, because generated content consists of boxes in the tree, no different from other boxes.) C.2.86 Section 12.3.2 Inserting quotes with the 'content' property Specified that extra 'close-quote's and 'no-close-quote's (those without a matching 'open-quote' or 'no-open-quote') are not rendered, and that neither 'close-quote' nor 'no-close-quote' cause the quoting depth to be negative. C.2.87 Section 12.4 Automatic counters and numbering Defined what a rule with duplicate counters, such as 'counter-reset: section 2 section', means. C.2.88 Section 12.4.1 Nested counters and scope The scope of a counter no longer defaults to the whole document, but starts at the first element that uses the counter. (This affects counters that are used without a prior 'counter-reset' to set the scope explicitly.) C.2.89 Section 12.5 Lists Removed text in section 12.5 (formerly 12.6) relating to the 'marker' display value. Removed the 'marker-offset' property (and thus former section 12.6.1). C.2.90 Section 12.5.1 Lists The list styles 'hebrew', 'armenian', 'georgian', 'cjk-ideographic', 'hiragana', 'katakana', 'hiragana-iroha' and 'katakana-iroha' have been removed due to lack of implementation experience. (They are expected to return in the CSS3 Lists module.) Removed the sentence that said that an unknown value for 'list-style-type' should cause the value 'decimal' to be used instead. Instead, normal parsing rules apply and cause the rule to be ignored. The size of list style markers without an intrinsic size is now defined. C.2.91 Chapter 13 Paged media The 'size', 'marks', and 'page' properties are not part of CSS 2.1. C.2.92 Section 13.2.2 Page selectors The requirement for UA's to honor different declarations for :left, :right, and :first pages has been softened to simplify implementations: the page area of the :first page may be used for :left and :right pages as well. C.2.93 Section 13.3.1 Page break properties UAs are now only required to apply the page break properties to block-level elements in the normal flow of the root element, not to other blocks.However, UAs are now permitted to apply these properties to elements other than block-level elements. Defined treatment of margins, borders, and padding when a page break splits a box. The 'page-break-inside' property no longer inherits. C.2.94 Section 13.3.3 Allowed page breaks The 'page-break-inside' property of all ancestors is checked for page-breaking restrictions, not just that of the breakpoint's parent. When dropping restrictions to find a page breaking opportunity, rule A is dropped together with B and D rather than together with C. Removed restriction on breaking within absolutely positioned boxes. C.2.95 Section 14.2.1 Background properties For 'background-position', the restriction that keywords cannot be combined with percentage or length values is removed. I.e., a value like: '25% top' is now allowed. Also, 'background-position' now applies to all elements, not just to block-level and replaced elements. User agents are no longer allowed to treat a value of 'fixed' for 'background-attachment' as 'scroll'. Instead they must ignore all such declarations as if 'fixed' were an invalid value. The size of background images without an intrinsic size is now defined. C.2.96 Section 14.3 Gamma correction The contents of this section is now a non-normative note. C.2.97 Chapter 15 Fonts The 'font-stretch' and 'font-size-adjust' properties have been removed in CSS 2.1. Font descriptors, the '@font-face' declaration, and all associated parts of the font matching algorithm have been removed in CSS 2.1. C.2.98 Section 15.2 Font matching algorithm In this section (previously 15.5), in step 5 (previously 8) of the font matching algorithm, the UA is now allowed to use multiple default fallback fonts to find a glyph for a given character. In the per-property rule 2, specified that if there is only a small-caps font in a given family, then that font will be selected by 'normal'. C.2.99 Section 15.2.2 Font family The "missing character" glyph is no longer considered a match for the last font in a font set, but is now considered a match for U+FFFD. Certain punctuation characters when appearing in unquoted font family names are now required to be escaped. C.2.100 Section 15.5 Small-caps The 'font-variant' property's effect is no longer restricted to bicameral scripts. C.2.101 Section 15.6 Font boldness The computed value of 'font-weight' has been defined more precisely such that the 'bolder' and 'lighter' values have an appropriate effect when inheriting through elements with different font-families. C.2.102 Section 15.7 Font size Removed suggestion of 1.2 fixed ratio between keyword font sizes in favor of notes recommending a variable ratio and a smallest font-size no less than 9 pixels per EM unit. Added table mapping CSS font-size keywords to HTML font size numbers. C.2.103 Chapter 16 Text The 'text-shadow' property is not in CSS 2.1. C.2.104 Section 16.2 Alignment The initial value of 'text-align' is no longer UA-defined but a nameless value that acts as 'left' if 'direction' is 'ltr', 'right' if 'direction' is 'rtl'. The value for 'text-align' is not part of CSS 2.1. For 'text-align', specified that 'justify' is treated as the initial value when computed value of 'white-space' is 'pre' or 'pre-line'. C.2.105 Section 16.3.1 Underlining, over lining, striking, and blinking More precisely defined what boxes are affected by text decorations specified on a given element. Specified that underlines, overlines, and line-throughs apply only to text. Specified that an underline, overline, or line-through applied across a line must be at a constant vertical position and with a constant thickness across the entire line. Specified how text decorations are affected by relative positioning on descendants. User agents are now allowed to recognize the 'blink' value but not blink, whereas before they were required to ignore the 'blink' value if they chose not to support blinking text. Added text to allow older UAs to conform to this section if they follow CSS2's 'text-decoration' requirements but not the additional requirements in CSS2.1. C.2.106 Section 16.4 Letter and word spacing Support for the various values of 'letter-spacing' and 'word-spacing' is no longer optional. Specified that word spacing affects each space, non-breaking space, and ideographic space left in the text after white space processing rules have been applied. C.2.107 Section 16.5 Capitalization UAs are no longer allowed to not transform characters for which there is an appropriate transformation but which are outside of Latin-1. C.2.108 Section 16.6 White space The 'white-space' property now applies to all elements, not just to block-level elements. "\A" in generated content no longer forces a break for 'normal' and 'nowrap' values of 'white-space'. Specified that the CSS white space processing model assumes all newlines have been normalized to line feeds. Added section 16.6.1 to precisely define white space handling. Added section 16.6.3 to specify handling of control and combining characters. C.2.109 Chapter 17 Tables Moved all discussion of aural rendering and related properties to Appendix A. Updated prose to use the terms "specified", "computed" and "used" as appropriate when referencing values. (See changes to section 6.1.) C.2.110 Section 17.2 The CSS table model Defined handling of multiple 'table-header-group' and 'table-footer-group' elements. UAs are no longer allowed to ignore the table display values on arbitrary HTML elements, only on HTML table elements. C.2.111 Section 17.2.1 Anonymous table objects Changed rules so that internal table elements without an enclosing 'table' or 'inline-table' box generate an anonymous 'inline-table' rather than an anonymous 'table' when inside a "display: inline" parent element. The anonymous table object rules now treat anonymous boxes as equal to elements' boxes. Replaced several instances of the term "element" with "box", removed several instances of "(in the document tree)" and clarified that anonymous boxes generated in earlier rules are part of the input to later rules. Also replaced the term "object" with "box", as is used throughout the rest of the specification. HTML UAs are no longer exempt from the anonymous box generation rules. C.2.112 Section 17.4 Tables in the visual formatting model The relationship of the caption box, table box, and outer anonymous table box has been changed as follows: * The margins of the table box now apply to the outer (anonymous) table box that encloses both the table box and the caption(s), not to the inner table box. * The width of the anonymous box is now equal to the border-box width of the table box inside it instead of adapting to the widths and positions of both the table box and its captions. C.2.113 Section 17.4.1 Caption position and alignment The 'left' and 'right' values on 'caption-side' have been removed. C.2.114 Section 17.5 Visual layout of table contents Changed rule 5 in grid layout rules to allow overlapping of table cells instead of leaving skipping a gap in the grid to avoid overlap. C.2.115 Section 17.5.1 Table layers and transparency In point 6, changed 'These "empty" cells are transparent' to: If the value of their 'empty-cells' property is 'hide' these "empty" cells are transparent through the cell, row, row group, column, and column group backgrounds, letting the table background show through. C.2.116 Section 17.5.2.1 Fixed table layout Specified that in fixed table layout, extra columns in rows after the first must not be rendered. C.2.117 Section 17.5.2.2 Automatic table layout Restricted inputs to the table layout algorithm for 'table-layout: auto', whether or not the algorithm described in this section is used, to the width of the containing block and the content of, and any CSS properties set on, the table and any of its descendants. Added rule 4 to include the column group's width in the algorithm for determining column widths. C.2.118 Section 17.5.3 Table height algorithms The 'height' property on tables is now treated as a minimum height; the UA no longer has the option of using 'height' to constrain the size of the table to be smaller than its contents. The baseline of a cell is now defined much more precisely. Defined the baseline of a row with no baseline-aligned cells. C.2.119 Section 17.5.4 Horizontal alignment in a column The value for 'text-align' is not part of CSS 2.1. C.2.120 Section 17.6 Borders Several popular browsers assume an initial value for 'border-collapse' of 'separate' rather than 'collapse' or exhibit behavior that is close to that value, even if they do not actually implement the CSS table model. 'Separate' is now the initial value. C.2.121 Section 17.6.1 The separated borders model Specified the effect of padding on the table element. Specified which parts of the table are included in the width measurement. C.2.122 Section 17.6.1.1 Borders and Backgrounds around empty cells Refined definition of "empty" when used as a condition for the 'empty-cells' property so that it is not triggered when the cell includes any child elements, even if they are empty. The 'empty-cells' property now hides both borders and backgrounds, not just borders. Changed behavior of a row when it collapses due to 'empty-cells': it is no longer treated as "display: none". Instead it is given zero height and its associated border-spacing is eliminated. C.2.123 Section 17.6.2 The collapsing border model The outer half of the table borders no longer lie in the margin area. Specified which part of the table is considered the border are in the collapsed borders model and how its width is calculated. The edges of the box in which the table background is painted is, however left explicitly undefined. C.2.124 Section 17.6.2.1 Border conflict resolution Defined in rule 4 what happens when two elements of the same type conflict and their borders have the same width and style. C.2.125 Section 18.1 Cursors: the 'cursor' property The size of cursors without an intrinsic size is now defined. C.2.126 Section 18.4 Dynamic outlines Position of outline with respect to the border edge is now only suggested, not required. Conformant UAs are now allowed to ignore the 'invert' value. In such UAs the initial value of 'outline-color' is the value of the 'color' property. C.2.127 Chapter 12 Generated content, automatic numbering, and lists The 'marker' value for 'display' does not exist in CSS 2.1 C.2.128 Appendix A. Aural style sheets Chapter 19 on aural style sheets has become appendix A and is not normative in CSS 2.1. Related units (deg, grad, rad, ms, s, Hz, kHz) are also moved to this appendix, as is the 'speak-header' property from the "tables" chapter and other notes on aural table rendering. The 'aural' media type is deprecated in favor of the new 'speech' media type. C.2.129 Appendix A Section 5 Pause properties Changed the initial value of 'pause-before' and 'pause-after' to be 0 instead of UA-defined. A note has been added to this section (formerly 19.4) about the change in position and behavior of pauses in CSS3 Speech compared to this appendix. C.2.130 Appendix A Section 6 Cue properties This section (formerly Section 19.5) now specifies the placement of cues and pauses with respect to the :before and :after pseudo-elements. C.2.131 Appendix A Section 7 Mixing properties The keywords 'mix' and 'repeat' may now appear in either order. C.2.132 Appendix B Bibliography Various references in Appendix B (formerly Appendix E) have been updated as appropriate. Switched [CSS1] from Normative to Informative. Updated URI reference from [RFC1808] and the draft-fielding-uri-syntax-01.txt to [RFC3986]. Updated HTTP reference from [RFC2068] to [RFC2616]. Removed normative references to [IANA] and [ICC32]. Added normative references to [ICC42], [RFC3986], [RFC2070], [UAAG10]. Added informative references to CSS2, CSS3 Color, CSS3 Lists, Selectors, CSS3 Speech, DOM 3 Core, MathML 2, P3P, RFC1630, SVG 1.1, XHTML 1, XML ID, and XML Namespaces. Removed informative references to [ISO10179] (DSSSL), [INFINIFONT], [ISO9899] (C), [MONOTYPE], [NEGOT], [OPENTYPE], [PANOSE], [PANOSE2], [POSTSCRIPT], [RFC1866] (HTML 2), [RFC1942] (HTML Tables), [TRUETYPEGX], [W3CStyle]. Updated language tags references from [RFC1766] to [BCP47]. C.2.133 Other The former informative appendix C, "Implementation and performance notes for fonts," is left out of CSS 2.1. C.3 Errors C.3.1 Shorthand properties Shorthand properties take a list of subproperty values or the value 'inherit'. One cannot mix 'inherit' with other subproperty values as it would not be possible to specify the subproperty to which 'inherit' applied. The definitions of a number of shorthand properties did not enforce this rule: 'border-top', 'border-right', 'border-bottom', 'border-left', 'border', 'background', 'font', 'list-style', 'cue', and 'outline'. C.3.2 Applies to The "applies to" line of many property definitions has been made more accurate by excluding or including table display types where appropriate. C.3.3 Section 4.1.1 (and G2) DELIM should not have included single or double quote. Refer also to section 4.1.6 on strings, which must have matching single or double quotes around them. Removed "A-Z" from the "nmchar" token: as CSS is case insensitive anyway, it was redundant. Corrected "unicode" macro to treat CRLF as a single character. Corrected "block" production to allow white space between declarations. In the rule for "any" (in the core syntax), corrected "FUNCTION" to "FUNCTION any* ')'". C.3.4 Section 4.1.3 Characters and case Corrected third paragraph to say that an '@import' rule can only be preceded by an '@charset' rule or other '@import' rules. C.3.5 Section 4.3 (Double sign problem) Several values described in subsections of this section incorrectly allowed two "+" or "-" signs at their beginnings. C.3.6 Section 4.3.2 Lengths Fixed double sign error in definition of . ( already has a sign.) Corrected the suggested reference pixel to be based on a [INS: 96 dpi :INS] device, not 90 dpi. The visual angle is thus about [INS: 0.0213 degrees :INS] instead of 0.0227, and a pixel at arm's length is about [INS: 0.26 mm :INS] instead of 0.28 Corrected last sentence to refer to a unsupported used length, not an unsupported specified length. C.3.7 Section 4.3.3 Percentages Fixed double sign error in definition of . ( already has a sign.) C.3.8 Section 4.3.4 URLs and URIs Defined escaping requirements in terms of the URI token so that no escaping requirements are missing from the prose. Included invalid URIs in last paragraph about URI error handling. C.3.9 Section 4.3.5 Counters Corrected syntax of counter() and counters() notation to allow white space between tokens. C.3.10 Section 4.3.6 Colors Deleted the comments about range restriction after the following examples: em { color: rgb(255,0,0) } em { color: rgb(100%, 0%, 0%) } C.3.11 Section 4.3.7 Strings (Formerly section 4.3.10) Corrected text to allow all forms of Unicode escapes for U+000A, not just the "\A" form, for including newlines in strings. C.3.12 Section 5.10 Pseudo-elements and pseudo-classes In the second bullet, added that the ':lang()' pseudo-class can also be deduced from the document in some cases. C.3.13 Section 6.4 The cascade Removed paragraph about imported style sheets being overridden by rules in the importing style sheet: imported style rules follow the cascade as specified in 6.4.1 Cascading order, exactly as if they were inserted in place of the @import rule. C.3.14 Section 8.1 Box Dimensions The definition of "content edge" has been changed to depend on 'width' and 'height' rather than directly on 'rendered content'. From the definition of "padding edge", deleted the sentence "The padding edge of a box defines the edges of the containing block established by the box." For information about containing blocks, consult Section 10.1. C.3.15 Section 8.2 Example of margins, padding, and borders The colors in the example HTML did not match the colors in the image. C.3.16 Section 8.5.4 Border shorthand properties Changed various border shorthands' syntax definitions to use the , and <'border-top-color'> value types as appropriate. C.3.17 Section 9.2.1 Block-level elements and block boxes Excepted table elements from second paragraph about principal block boxes and their contents. Corrected sentence to say "either only block boxes or only inline boxes" instead of "only block boxes". C.3.18 Section 9.3.1 Choosing a positioning scheme In the definition of "position: static", added 'right' and 'bottom' to the sentence saying that 'top' and 'left' do not apply. C.3.19 Section 9.3.2 Box offsets The properties 'top', 'right', 'bottom', and 'left', incorrectly referred to offsets with respect to a box's content edge. The proper edge is the margin edge. Thus, for 'top', the description now reads: "This property specifies how far a box's top margin edge is offset below the top edge of the box's containing block." Corrected text under property definitions to say that for relatively-positioned elements, 'top', 'right', 'bottom', and 'left' define the offset from the box's position in the normal flow, not from the edges of the containing block. (The previous definition conflicted with that was further down; since that text is now redundant, it has been removed.) C.3.20 Section 9.4.1 Block formatting contexts In paragraph about relationship of a box's outer edges to its containing block's edges, corrected parenthetical to say that line boxes, not the content area, may shrink due to floats. C.3.21 Section 9.4.2 Inline formatting context Added "and the presence of floats" to "The width of a line box is determined by a containing block". C.3.22 Section 9.4.3 Relative positioning In the first paragraph, added "or floated" to the phrase "laid out according to the normal flow" as floated elements can be relatively positioned but are not part of the normal flow. C.3.23 Section 9.5 Floats Corrected sentence about not enough horizontal room for the float to say that it is shifted downward until either it fits or there are no more floats present. C.3.24 Section 9.5.1 Positioning the float Correct "Applies to" line and prose to say that the 'float' property can be set for any element but only applies to elements that are not absolutely positioned. C.3.25 Section 9.5.2 Controlling flow next to floats Removed sentence saying that 'clear' may only be specified for block-level elements: it can be specified for any element, it only applies to block-level elements. C.3.26 Section 9.6 Absolute positioning Corrected sentence that said absolutely positioned boxes establish a new containing block for absolutely positioned descendants to except fixed positioned descendants. C.3.27 Section 9.7 Relationships between 'display', 'position', and 'float' In rule 1, corrected "user agents must ignore 'position' and 'float" to "'position' and 'float' do not apply". C.3.28 Section 9.10 Text direction Corrected note about 'direction' on table column elements to say that "columns are not the ancestors of the cells in the document tree" rather than saying "columns do not exist in the document tree". Added table cells, table captions, and inline blocks alongside block-level elements in description of 'bidi-override' value. Also corrected the prose to handle anonymous child blocks. Updated mention of Unicode's embedding limit from 15 to 61. C.3.29 Section 10.1 Definition of "containing block" Included table cells (and inline blocks) together with block-level elements in rule 2 defining the containing block of non-absolutely-positioned elements. C.3.30 Section 10.3.3 Block-level, non-replaced elements in normal flow In the last sentence of the paragraph following the equation ("If the value of 'direction' is 'ltr', this happens to 'margin-left' instead") substituted 'rtl' for 'ltr'. C.3.31 Section 10.4 Minimum and maximum widths The initial value for 'min-width' is now '0' rather than UA-dependent. Corrected "applies to" exception for both 'min-width' and 'max-width' from "table elements" to "table rows and row groups". Specified that negative values for 'min-width' and 'max-width' are illegal. C.3.32 Section 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' Added that 'auto' height also depends on whether the element has padding or borders, as these influence margin-collapsing behavior. Added text to correctly account for margin collapsing behavior. C.3.33 Section 10.7 Minimum and maximum heights Corrected "applies to" exception for both 'min-width' and 'max-width' from "table elements" to "table columns and column groups". Specified that negative values for 'min-height' and 'max-height' are illegal. C.3.34 Section 11.1.1 Overflow Corrected "applies to" line for 'overflow' from "block-level and replaced elements" to "non-replaced block-level elements, table cells, and inline-block elements". The example of a DIV element containing a BLOCKQUOTE containing another DIV was not rendered correctly. The first style rule applied to both DIVs, so the second DIV box should have been rendered with a red border as well. The second DIV has now been changed to a CITE, which does not have a red border. C.3.35 Section 11.1.2 Clipping: the 'clip' property Corrected "rect ( )" to "rect( , , , )". C.3.36 Section 11.2 Visibility Corrected initial value of 'visibility' to 'visible'. C.3.37 Section 12.4.2 Counter styles The example used the style 'hebrew', which does not exist in CSS level 2. Changed to 'lower-greek'. C.3.38 Section 12.6.2 Lists Under the 'list-style' property, the example: ul > ul { list-style: circle outside } /* Any UL child of a UL */ could never match valid HTML markup (since a UL element cannot be a child of another UL element). An LI has been inserted in between. C.3.39 Section 14.2 The background Second sentence: "In terms of the box model, 'background' refers to the background of the content and the padding areas" now also mentions the border area. (See also errata to section 8.1 above.) Thus: In terms of the box model, "background" refers to the background of the content, padding and border areas. C.3.40 Section 14.2.1 Background properties Under 'background-image', defined the image tile size used when the background image has intrinsic sizes specified in percentages or no intrinsic size. Under 'background-repeat', the sentence "All tiling covers the content and padding areas [...]" has been corrected to "All tiling covers the content, padding [INS: and border :INS] areas [...]". Under 'background-attachment', the value 'scroll' is defined to scroll with the "containing block" rather than with the "document". Also the sentence "Even if the image is fixed [...] background or padding area of the element" has been corrected to Even if the image is fixed, it is still only visible when it is in the background, padding [INS: or border :INS] area of the element. C.3.41 Section 15.2 Font matching algorithm In bullet 2, changed "the UA uses the 'font-family' descriptor" to "the UA uses the 'font-family' property". C.3.42 Section 15.7 Font size The statement "Negative values are not allowed" for 'font-size' now applies to percentages as well as lengths. C.3.43 Section 16.1 Indentation Corrected 'text-indent' to apply to table cells (and inline blocks) as well as block-level elements. C.3.44 Section 16.2 Alignment Corrected 'text-align' to apply to table cells (and inline blocks) as well as block-level elements. Changed prose about the effect of 'justify' to be less correct. Corrected the note to say that justification is also dependent on the script, not just the language, of the text. C.3.45 Section 17.2 The CSS table model In the definition of table-header-group, changed "footer" to "header" in "Print user agents may repeat footer rows on each page spanned by a table." C.3.46 Section 17.2.1 Anonymous table objects Added 'table-header-group' and 'table-footer-group' alongside mentions of 'table-row-group' where missing. Corrected 'caption' to 'table-caption'. Added missing rule (#3) for 'table-column' boxes. Added 'table-caption' and 'table-column-group' to list of boxes requiring a 'table' or 'inline-table' parent in rule 4. Added rules 5 and 6 to generate 'table-row' boxes where necessary for children of 'table'/'inline-table' and 'table-row-group'/'table-header-group'/'table-footer-group' boxes. C.3.47 Section 17.4 Tables in the visual formatting model Specified handling of multiple caption boxes. Specified that the anonymous outer table box is a 'block' box if the table is block-level and an 'inline-block' box if the table is inline-level but that the anonymous outer table box cannot accept run-ins. C.3.48 Section 17.5 Visual layout of table contents Correct text that said all internal table elements have padding; change to say that of these only table cells have padding. The following note: Note. Table cells may be relatively and absolutely positioned, but this is not recommended: positioning and floating remove a box from the flow, affecting table alignment. has been amended as follows: Note. Table cells may be positioned, but this is not recommended: absolute and fixed positioning, as well as floating, remove a box from the flow, affecting table size. C.3.49 Section 17.5.1 Table layers and transparency The rows and columns only cover the whole table in the collapsed borders model, not in the separated borders model. The points 2, 3, 4 and 5 have been corrected to define the area covered by rows, columns, row groups and column groups and thus the positioning and painting of backgrounds on those elements. Specify the handling of "missing cells". C.3.50 Section 17.6.1 The separated borders model In the image, changed "cell-spacing" to "border-spacing". C.3.51 Section 18.2 System Colors For the 'ButtonHighlight' value, changed the description from "Dark shadow" to "Highlight color". C.3.52 Section E.2 Painting order Changed "but any descendants which actually create a new stacking context" to "but any [INS: positioned descendants and :INS] descendants which actually create a new stacking context" (3 times). This change also occurred once in section 9.5 (Floats) and once in section section 9.9 (Layered presentation). C.4 Clarifications C.4.1 Section 2.1 A brief CSS 2.1 tutorial for HTML This section has been marked non-normative. C.4.2 Section 2.2 A brief CSS 2.1 tutorial for XML This section has been marked non-normative. Added a statement about case-sensitivity of selectors for XML. The specification for the XML style sheet PI was written after CSS2 was finalized. The first line of the full XML example should not have been be , but C.4.3 Section 2.3 The CSS 2.1 processing model This section has been marked non-normative. C.4.4 Section 3.1 Definitions Added a note to clarify that the deprecated/non-deprecated status of a feature is distinct from its normative/non-normative status. Under 'document language' clarified that CSS only describes the presentation of a document language, and has no effect on its semantics. Changed definition of 'replaced element' to "an element whose content is outside the scope of the CSS formatting model" and added further clarifying text. This clarifies that e.g., SVG images embedded in an XML document are also considered replaced elements, not just those linked in from an outside file. Also changed definition of 'rendered content' to be consistent with this clarification. Added under "Intrinsic dimension" that raster images without reliable resolution information are assumed to have a size of 1 px unit per image source pixel. Added definition for 'ignore'. Added definition for 'HTML user agent'. Added definition for 'property'. C.4.5 Section 4.1 Syntax Moved definitions of "immediately before" and "immediately after" forward so they apply to the whole Syntax section. Added sections 4.1.2.1 and 4.1.2.2 to defined vendor-specific extensions. C.4.6 Section 4.1.1 Tokenization Clarified that input that cannot be parsed according to the core syntax is ignored according to the rules for handling parsing errors. Clarified that input that cannot be tokenized or parsed has no meaning in CSS2.1. C.4.7 Section 4.1.3 Characters and case Clarified that when a CRLF pair terminates an escape sequence, the pair is treated as a single white space character as corrected in the tokenization rules. Replaced "[a-z0-9]" by "[a-zA-Z0-9]" as an extra reminder that CSS identifiers are case-insensitive. C.4.8 Section 4.1.7 Rule sets, declaration blocks, and selectors Replaced the term "{}-block" with "declaration block". C.4.9 Section 4.2 Rules for handling parsing errors Clarified that all property:value combinations and @-keywords that do not contain an identifier beginning with dash or underscore are reserved by CSS for future use. Clarified that when something inside an at-rule is ignored because it is invalid, this does not make the entire at-rule invalid. Referenced section 4.1.7 for parsing invalid bits inside declaration blocks. C.4.10 Section 4.3.1 Integers and real numbers Clarified that '-0' is equivalent to '0' and is not a negative number. C.4.11 Section 4.3.2 Lengths Clarified that negative length values on properties that do not allow them cause the declaration to be ignored. C.4.12 Section 4.3.4 URLs and URIs Reduced unnecessary discussion of what a URI is. C.4.13 Section 5.1 Pattern matching Added note about terminology change ("simple selector") between CSS2 and CSS3. C.4.14 Section 5.7 Adjacent sibling selectors Clarified that text nodes and comments do not affect whether a sibling selector matches. C.4.15 Section 5.8.1 Matching attributes and attribute values Clarified ~= and |= by using the definitions from the Selectors module. C.4.16 Section 5.8.2 Default attribute values in DTDs Clarified that rules about default attribute values are the same, whether the default is specified in a DTD or by other means. C.4.17 Section 5.9 ID selectors Added a note that it depends on the document format which attributes are ID attributes. C.4.18 Section 5.11.3 The dynamic pseudo-classes: :hover, :active, and :focus Clarified that CSS 2.1 does not define if the parent of an element that matches ':active' or ':hover' itself also matches ':active' or ':hover'. Added note that, in CSS1, ':active' only applies to links. C.4.19 Section 5.11.4 The language pseudo-class: :lang Added a note to show the differences between ':lang(xx)' and '[lang=xx]'. C.4.20 Section 5.12.2 The :first-letter pseudo-element Clarified that digits can also be first letter. C.4.21 Section 6.2 Inheritance Clarified that computed values are inherited (not specified values) and that they become the specified value on the inheritor. Removed discussion of "default" styles for a document. C.4.22 Section 6.2.1 The 'inherit' value Clarify that 'inherit' can be used on properties that are not normally inherited and that when set on the root element, it has the effect of assigning the property's initial value. C.4.23 Section 6.3 The @import rule Except @charset from the statement that @imports must precede all other rules. C.4.24 Section 6.4 The Cascade Obfuscated note about system settings and UA limitations. C.4.25 Section 6.4.1 Cascading order Various editorial changes to clarify sort order. C.4.26 Section 6.4.3 Calculating a selector's specificity Added a note: The specificity is based only on the form of the selector. In particular, a selector of the form "[id=p33]" is counted as an attribute selector (a=0, b=1, c=0), even if the id attribute is defined as an "ID" in the source document's DTD. C.4.27 Section 7.2.1 The @media rule Clarify that Style rules outside of @media rules apply to the same media types that the style sheet itself applies to. C.4.28 Section 7.3 Recognized media types Added text to clarify that media types are mutually exclusive, but a UA can render simultaneously to canvases with different media types. C.4.29 Section 7.3.1 Media groups Split "aural" media group into "audio" and "speech". C.4.30 Section 8.1 Box dimensions * The terms "content box", "padding box", "border box", and "margin box" have been defined. * Border backgrounds are not specified by border properties. Changed the last paragraph of 8.1 to: The background style of the content, padding, and border areas of a box is specified by the 'background' property of the generating element. Margin backgrounds are always transparent. * Removed definition of "box width" and "height". C.4.31 Section 8.3 Margin properties Added a sentence to note that vertical margins have no effect on non-replaced inline elements. C.4.32 Section 8.3.1 Collapsing margins Changed "absolute maximum" to "maximum of the absolute values" in sentence about negative margins collapsing. Added this clarifying note to the first bullet of the explanation of vertical collapsing of margins: Note. Adjoining boxes may be generated by elements that are not related as siblings or ancestors. Emphasized that floating elements' margins do not collapse even between a float and its in-flow children. Emphasized that absolutely positioned elements' margins do not collapse even between the positioned element and its in-flow children. C.4.33 Section 8.5.3 Border style Changed description of 'none' value to not imply that all four border widths are set to zero. C.4.34 Section 9.1.1 The viewport Changed the sentence "When the viewport is smaller than the ..., the user agent should offer a scrolling mechanism" to use "area of the canvas on which the document is rendered" instead of "document's initial containing block". C.4.35 Section 9.2.4 The 'display' property Clarified that 'display: none' also applies to non-visual media. C.4.36 Section 9.3.1 Choosing a positioning scheme Clarified that the margins of fixed positioned boxes do not collapse with any other margins. Clarified that in print media fixed boxes are rendered on every page. C.4.37 Section 9.3.2 Box offsets Clarified that negative lengths and percentages are allowed as values of 'top', 'right', 'bottom', and 'left'. Added "For replaced elements, the effect of this value depends only on the intrinsic dimensions of the replaced content. See the sections on the width and height of absolutely positioned, replaced elements for details." to the definition of 'auto' because that's not what chapter 10 says at all. C.4.38 Section 9.4.2 Inline formatting context Clarified that 'justify' stretches "spaces and words in inline boxes"; previous text simply said that it stretches "inline boxes". The statement "When an inline box is split, margins, borders, and padding have no visual effect where the split occurs." has been generalized. Margins, borders, and padding have no visual effect where one or more splits occur. Clarified that an inline box that exceeds the width of a line box and cannot be split therefore overflows the line box. Removed sentence about formatting of margins, borders, and padding for split inline boxes not being fully defined when affected by bidi as that situation is now defined in section 8.6. C.4.39 Section 9.4.3 Relative positioning Clarified that although relative positioning normally does not directly affect layout, it may affect layout indirectly through the creation of scrollbars. Relatively positioned boxes do not always establish new containing blocks. Changed the second paragraph to refer to the section on containing blocks accordingly. The paragraph about dynamic movement and superscripting has been shifted into a non-normative note. C.4.40 Section 9.5 Floats Clarified that line boxes are shortened to make room for the margin box of the float. Added some text to clarify what "Any content in the current line before a floated box is reflowed in the first available line on the other side of the float" means. Clarified floats' position in the stacking order. C.4.41 Section 9.5.1 Positioning the float Clarified that the elements referenced in the float behavior rules are in the same block formatting context as the float. C.4.42 Section 9.5.2 Controlling flow next to floats Clarified that the effects of 'clear' do not consider floats in other block formatting contexts. C.4.43 Section 9.8 Comparison of normal flow, floats, and absolute positioning Added a note to clarify that the images in this section are not drawn to scale and are illustrations, not reference renderings. C.4.44 Section 10.1 Definition of "containing block" Noted that a containing block formed by inline elements may wind up with a negative containing block width. C.4.45 Section 10.2 Content width In the definition of values for the 'width' property, changed "Specifies a fixed width" to "Specifies the width of the content area using a length unit". C.4.46 Section 10.3.3 Block-level, non-replaced elements in normal flow Clarified that setting both left and right margins to 'auto' horizontally centers the element within its containing block. C.4.47 Section 10.3.8 Absolutely positioning, replaced elements Clarified which part of the text of section 10.3.7 is re-used. C.4.48 Section 10.4 Minimum and maximum widths Clarified that 'min-width' and 'max-width' do not affect the computed values of any properties. (They only affect the used value.) C.4.49 Section 10.6 Calculating heights and margins Clarified that these rules apply to the root element just as to any other element. C.4.50 Section 10.7 Minimum and maximum heights Clarified that 'min-width' and 'max-width' do not affect the computed values of any properties. (They only affect the used value.) C.4.51 Section 10.8 Line height calculations Removed clarifying note about line height being taller than tallest single inline box due to vertical alignment. C.4.52 Section 10.8.1 Leading and half-leading Removed "slightly" from the note "Values of this property have [DEL: slightly :DEL] different meanings in the context of tables." C.4.53 Section 11.1 Overflow and clipping Clarified when absolute positioning and negative margins cause overflow. Added 'text-indent' to the list of things that can cause overflow. Removed mention of 'clip' since it no longer affects most elements; mentioned that the 'overflow' property also specifies whether a scrolling mechanism is provided to access clipped content. C.4.54 Section 11.1.1 Overflow Clarified that descendant elements whose containing block is the viewport or an ancestor of the element are not affected by overflow clipping. Removed unnecessary mentions of the 'clip' property from the 'hidden' value definition. C.4.55 Section 11.1.2 Clipping Changed "portion of an element's rendered content" to "portion of an element's border box" since clipping also affects the element's backgrounds and borders. Clarified what parts of the element are affected by clipping. Clarified that clipped content does not cause overflow. Clarified that arguments of clip() can be separated by spaces or by commas, but not a combination. C.4.56 Section 11.2 Visibility Clarified that descendants of a 'visibility: hidden' element will be visible if they have 'visibility: visible'. C.4.57 Section 12.1 The :before and :after pseudo-elements Clarified that :before and :after pseudo-elements interact with other boxes as if they were real elements just inside their associated element. Noted that the interaction of :before and :after with replaced elements is left undefined for now. C.4.58 Section 12.2 The 'content' property Clarified which counters are used for counter() and counters() in case there are multiple counters of the same name. C.4.59 Section 12.3.2 Inserting quotes with the 'content' property Removed note about common typographic practices when quotes in different languages are mixed. C.4.60 Section 12.4 Automatic counters and numbering In the "self-nesting" behavior of counters, clarified that merely using a counter in a child element does not create a new instance of it: only resetting it does. Clarified that the scope of a counter does not include any elements in the scope of a counter with the same name created by a 'counter-reset' on a later sibling or a later 'counter-reset' on the same element. Removed sentence about scope of 'counter-increment' without prior 'counter-reset' as that is now defined (differently) under "12.4.1 Nested counters and scope." C.4.61 Section 12.4.3 Counters in elements with 'display: none' Clarified that pseudo-elements that generate no boxes also do not increment counters. C.4.62 Section 14.2 The background Clarified that the root background image, although painted over the entire canvas, is anchored as if painted only for the root element, and that the root's background is only painted once. Clarified rules for propagation of background settings on HTML's element to the root. Added statement about z-index of backgrounds for elements that form a stacking context and referred to z-index property for details. Added this note after the first paragraph after 'background-attachment': Note that there is only one viewport per document. I.e., even if an element has a scrolling mechanism (see 'overflow'), a 'fixed' background does not move with it. Definition of 'background-position' has been rewritten as normative rules rather than just examples. Stated that the tiling and positioning of background images for inline elements is undefined in CSS2.1. C.4.63 Section 15.1 Fonts Introduction Drastically shortened introduction. C.4.64 Section 15.2 Font matching algorithm In the per-property rule 2, clarified that 'normal' matches the non-small-caps variant (if there is one). C.4.65 Section 15.2.2 Font family Removed discussion of font-matching algorithm. (It is already covered in the font-matching algorithm's own section. Clarified that quoted strings that are the same as a keyword value must be treated as font family names and not as the keyword value (which must be unquoted). C.4.66 Section 15.3.1 Generic font families This section, previously section 15.2.6, has been moved but no other change was made. C.4.67 Section 15.4 Font styling The text for this section (formerly part of 15.2.3) has been reverted to its CSS1 format. C.4.68 Section 15.5 Small-caps The text for this section (formerly part of 15.2.3) has been reverted to its CSS1 format. Clarified that CSS2.1 cannot select font variants besides small-caps. Clarified that when "font-variant: small-caps" results in the substitution of full-caps, the behavior is the same as for text-transform. C.4.69 Section 15.6 Font boldness The text for this section (formerly part of 15.2.3) has been reverted to its CSS1 format. Also, discussion of font-weight from other parts of the Fonts chapter has been aggregated under this section. Removed statement that says "User agents must map names to values in a way that preserves visual order; a face mapped to a value must not be lighter than faces mapped to lower values." This is otherwise implied by "The only guarantee is that a face of a given value will be no less dark than the faces of lighter values." C.4.70 Section 15.7 Font size Clarified relationship of font size to em squares. Added a totally irrelevant note about font sizes virtual reality scenes. C.4.71 Section 16.1 Indentation Clarified that text overflowing due to text-indent is affected by the 'overflow' property. Added a note about text-indents inheriting behavior and suggesting 'text-indent: 0' on inline-blocks. C.4.72 Section 16.2 Alignment Changed "double justify" to "justify" under "left, right, center, and justify". C.4.73 Section 16.3.1 Underlining, over lining, striking, and blinking Added an example to illustrate how underlining affects descendant boxes. C.4.74 Section 16.5 Capitalization Switched language reference from RFC2070 to BCP47. C.4.75 Section 16.6 White space Added section 16.6.1 as an example to illustrate the interaction of white space collapsing and bidi. C.4.76 Section 17.1 Introduction to tables Expanded introduction to include a brief discussion of the two table layout models. Mentioned that the automatic table algorithm is not fully defined in CSS 2.1 but that some implementations have achieved relatively close interoperability. C.4.77 Section 17.2 The CSS table model Clarify that all table captions must be rendered if more than one exists. Specified that replaced elements with table display values are treated as table elements in table layout. C.4.78 Section 17.2.1 Anonymous table objects Moved the first bullet text to the prose before the list of generation rules as it is a general statement of what the rules are supposed to accomplish. C.4.79 Section 17.4 Tables in the visual formatting model Clarified that "display: table" elements behave as block-level elements and "display: inline-table" elements behave as inline-level elements and not the other way around. Clarified that 'table-caption' boxes behave as normal block boxes within the outer anonymous table box. Clarified that percentage 'width' and 'height' on the table box is relative to the anonymous box's containing block, not the anonymous box itself. Clarified that the 'position', 'float', 'top', 'right', 'bottom', and 'left' values on the table box are used on the anonymous outer box instead of the table box and that the table box itself uses the initial values of those properties. C.4.80 Section 17.5 Visual layout of table contents To remove ambiguity about the position of extent of internal table boxes, the following paragraph was added after point 6: the edges of the rows, columns, row groups and column groups in the collapsing borders model coincide with the hypothetical grid lines on which the borders of the cells are centered. (And thus, in this model, the rows together exactly cover the table, leaving no gaps; ditto for the columns.) In the separated borders model, the edges coincide with the border edges of cells. (And thus, in this model, there may be gaps between the rows and columns, corresponding to the 'border-spacing' property.) Changed warning note about positioning of table cells to be more precise about the possibly unintended effects. C.4.81 Section 17.5.1 Table layers and transparency At the end of the section added the following paragraph: Note that if the table has 'border-collapse: separate', the background of the area given by the 'border-spacing' property is always the background of the table element. See 17.6.1 C.4.82 Section 17.5.2 Table width algorithms Added a paragraph to clarify the interaction of the table width algorithms with the rules in section 10.3 (Calculating widths and margins). C.4.83 Section 17.5.2.1 Fixed table layout Explicitly mentioned that the fixed table layout algorithm may be used with the algorithm of section 10.3.3 when 'table-layout' is 'fixed' but 'width' is 'auto'. C.4.84 Section 17.5.2.2 Automatic table layout Clarified that UAs can use other algorithms besides the one in this section even if it results in different behavior. Also marked the rest of the section non-normative in accordance with that statement. C.4.85 Section 17.5.4 Horizontal alignment in a column Changed "The horizontal alignment of a cell's content within a cell box is specified with the 'text-align' property" to "The horizontal alignment of a cell's [INS: inline content :INS] within a cell box [INS: can be :INS] specified with the 'text-align' property." C.4.86 Section 17.5.5 Dynamic row and column effects Clarified that not affecting layout means that 'visibility: collapse' causes the part of row- and column-spanning cells that span into the collapsed row to be clipped. C.4.87 Section 17.6.1 The separated borders model Added a note explaining that 'border-spacing' can be used as a substitute for the non-standard 'framespacing' attribute on frameset elements (which are out-of-scope for CSS2.1). Added clarification about backgrounds: the sentence "This space is filled with the background of the table element" was replaced by: In this space, the row, column, row group, and column group backgrounds are invisible, allowing the table background to show through. C.4.88 Section 17.6.2 The collapsing borders model In the sentence after the question, added "and padding-left[i] and padding-right[i] refer to the left (resp., right) padding of cell i." C.4.89 Section 18.2 System Colors Noted that system colors are deprecated in CSS3. C.4.90 Section 18.4 Dynamic outlines Clarified that outlines do not cause overflow. Clarified that outlines are only fully connected "if possible". C.4.91 Section 18.4.1 Outlines and the focus Clarify that changing outlines in response to focus should not cause a document to reflow. C.4.92 Appendix D Default style sheet for HTML 4 Added paragraph clarifying that some presentational markup in HTML can be replaced with CSS, but it requires different markup. C.5 Errata since the Candidate Recommendation of July 2007 Errata to CSS 2.1 since CR version of July 19, 2007. C.5.1 Section 1.4.2.1 Value [2009-04-15] The notation â&&â may be used in syntax definitions in future CSS specifications. C.5.2 Section 2.3 The CSS 2.1 processing model [2008-08-19] The first part of the section is not normative. C.5.3 Section 3.1 Definitions [2007-11-14] Append "[INS: For raster images without reliable resolution information, a size of 1 px unit per image source pixel must be assumed. :INS] " to the definition of "intrinsic dimensions." C.5.4 Section 4.1.1 Tokenization [2007-09-27] Remove "DELIM?" from the grammar rule declaration : [DEL: DELIM? :DEL] property S* ':' S* value; The DELIM was allowed there so that unofficial properties could start with a dash (-), but the dash was already allowed because of the definition of "IDENT." [2009-02-02] Change [DEL: U :DEL] to [INS: u :INS] in token UNICODE-RANGE. (It means the same, but seems to avoid confusion.) [2009-02-02] Clarify where comments are allowed: COMMENT tokens do not occur in the grammar (to keep it readable), but any number of these tokens may appear anywhere [DEL: between :DEL] [INS: outside :INS] other tokens. [INS: (Note, however, that a comment before or within the @charset rule disables the @charset.) :INS] C.5.5 Section 4.1.2.2 Informative Historical Notes [2008-12-09] Other known vendor prefixes are: -xv-, -ah-, prince-, -webkit-, and -khtml-. C.5.6 Section 4.1.3 Characters and case [2007-11-14] In the second bullet, change "[DEL: [a-z0-9] :DEL] " to "[INS: [a-zA-Z0-9] :INS] "; in the third bullet, change "[DEL: [0-9a-f] :DEL] " to "[INS: [0-9a-fA-F] :INS] ". Although the preceding bullet already says that CSS is case-insensitive, the explicit mention of upper and lower case letters helps avoid mistakes. C.5.7 Section 4.1.3 Characters and case [2008-03-05] CSS is now case-sensitive, except for certain parts: All CSS syntax is case-insensitive [INS: within the ASCII range (i.e., [a-z] and [A-Z] are equivalent) :INS] , except for parts that are not under the control of CSS. C.5.8 Section 4.1.3 Characters and case [2008-12-02] The pair â*/â ends a comment, even if preceded by a backslash. Change this sentence in the third bullet: [INS: Except within CSS comments, :INS] any character (except a hexadecimal digit) can be escaped with a backslash to remove its special meaning. C.5.9 Section 4.1.3 Characters and case [2009-04-15] Text added to match the grammar: [â¦] any character (except a hexadecimal digit [INS: , linefeed, carriage return or form feed :INS] ) can be escaped [â¦] C.5.10 Section 4.1.5 At-rules [2009-04-15] Clarified that unknown statements are ignored when looking for @import: CSS 2.1 user agents must ignore any '@import' rule that occurs inside a block or after any [DEL: valid :DEL] [INS: non-ignored :INS] statement other than an @charset or an @import rule. C.5.11 Section 4.1.7 Rule sets, declaration blocks, and selectors [2008-11-26] More precise statement of what is ignored: When a user agent cannot parse the selector (i.e., it is not valid CSS 2.1), it must ignore the [INS: selector and the following :INS] declaration block [INS: (if any) :INS] as well. C.5.12 Section 4.2 Rules for handling parsing errors [2009-04-15] Added error recovery rule for unexpected tokens at the top level: Malformed statements. User agents must handle unexpected tokens encountered while parsing a statement by reading until the end of the statement, while observing the rules for matching pairs of (), [], {}, "", and '', and correctly handling escapes. For example, a malformed statement may contain an unexpected closing brace or at-keyword. E.g., the following lines are all ignored: p @here {color: red} /* ruleset with unexpected at-keyword "@here" */ @foo @bar; /* at-rule with unexpected at-keyword "@bar" */ }} {{ - }} /* ruleset with unexpected right brace */ ) [ {} ] p {color: red } /* ruleset with unexpected right parenthesis */ C.5.13 Section 4.2 Rules for handling parsing errors [2008-11-26] Change âor blockâ as follows: User agents must ignore an invalid at-keyword together with everything following it, up to and including the next semicolon (;), [DEL: or block ({...}) :DEL] [INS: the next block ({...}), or the end of the block (}) that contains the invalid at-keyword :INS] , whichever comes first. C.5.14 Section 4.3.2 Lengths [2008-08-19] Add recommendation about size of px: [â¦] the user agent should rescale pixel values. [INS: It is recommended that the pixel unit refer to the whole number of device pixels that best approximates the reference pixel. :INS] C.5.15 Section 4.3.5 Counters [2008-03-05] Insert "case-sensitive" in "Counters are denoted by [INS: case-sensitive :INS] identifiers". C.5.16 Section 5.8.1 Matching attributes and attribute values [2008-04-07] Clarified ~= and |= by using the definitions from the Selectors module. [2008-11-03] Clarified that [foo~=""] (i.e., with an empty value) will not match anything. C.5.17 Section 5.8.2 Default attribute values in DTDs [2007-11-14] Replace "[DEL: tag :DEL] selector" by "[INS: type :INS] selector". C.5.18 Section 5.11.4 The language pseudo-class: :lang [2009-04-15] The language code is case-insensitive. C.5.19 Section 5.12.3 The :before and :after pseudo-elements [2008-11-03] Clarified text: When the :first-letter and :first-line pseudo-elements are [DEL: combined with :DEL] [INS: applied to an element having content generated using :INS] :before and :after, they apply to the first letter or line of the element including the [DEL: inserted text :DEL] [INS: generated content :INS] . C.5.20 Section 6.3 The @import rule [2008-08-19] Add âIn CSS 2.1â and âSee the section on parsing for when user agents must ignore @import rulesâ to [INS: In CSS 2.1, :INS] any @import rules must precede all other rules (except the @charset rule, if present). [INS: See the section on parsing for when user agents must ignore @import rules. :INS] C.5.21 Section 6.3 The @import rule [2008-11-26] Define what it means to import a style sheet twice and how the media list is matched. Add at the end: In the absence of any media types, the import is unconditional. Specifying 'all' for the medium has the same effect. [INS: The import only takes effect if the target medium matches the media list. :INS] [INS: A target medium matches a media list if one of the items in the media list is the target medium or 'all'. :INS] [INS: Note that Media Queries [MEDIAQ] extends the syntax of media lists and the definition of matching. :INS] [INS: When the same style sheet is imported or linked to a document in multiple places, user agents must process (or act as though they do) each link as though the link were to a separate style sheet. :INS] C.5.22 Section 6.4.1 Cascading order [2007-11-22] Spelling error: "prece[DEL: n :DEL] dence". C.5.23 Section 6.4.1 Cascading order [2008-11-26] Define the meaning of a media list: Find all declarations that apply to the element and property in question, for the target media type. Declarations apply if the associated selector matches the element in question [INS: and the target medium matches the media list on all @media rules containing the declaration and on all links on the path through which the style sheet was reached. :INS] C.5.24 Section 7.2.1 The @media rule [2008-12-02] The rules for parsing unknown statements inside @media blocks were ambiguous. Change the first sentence as follows: An @media rule specifies the target media types (separated by commas) of a set of [DEL: rules :DEL] [INS: statements :INS] (delimited by curly braces). [INS: Invalid statements must be ignored per 4.1.7 "Rule sets, declaration blocks, and selectors" and 4.2 "Rules for handling parsing errors." :INS] Also make it explicit that CSS level 2 (unlike higher levels) has no nested @-rules. Add at the end of the section: â[INS: At-rules inside @media are invalid in CSS 2.1. :INS] â C.5.25 Section 8.3.1 Collapsing margins [2008-08-18] In bullet 6, sub-bullet 2, the position of the top border edge is determined by assuming the element has a non-zero bottom (not: top) border. C.5.26 Section 8.3.1 Collapsing margins [2009-02-02] Rephrased the rule for adjoining margins so that the 'min-height' and 'max-height' of an element have no influence over whether the element's bottom margin is adjoining to its last child's bottom margin. C.5.27 Section 8.3.1 Collapsing margins [2008-12-02] Not only elements with 'overflow' other than 'visible', but all block formatting contexts avoid collapsing their margins with their children. Change the third bullet as follows: * Vertical margins of elements [DEL: with 'overflow' other than 'visible' :DEL] [INS: that establish new block formatting contexts (such as floats and elements with 'overflow' other than 'visible') :INS] do not collapse with their in-flow children. C.5.28 Section 9.2.2 Inline-level elements and inline boxes [2008-12-02] Added missing 'inline-block' in: âSeveral values of the 'display' property make an element inline: 'inline', 'inline-table', [INS: 'inline-block' :INS] and 'run-in' (part of the time; see run-in boxes).â C.5.29 Section 9.2.4 The 'display' property [2008-04-07] Clarified that 'display: none' also applies to non-visual media. C.5.30 Section 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' [2008-08-19] Remove true but confusing note (occurs 4Ã): [DEL: Note: For absolutely positioned elements whose containing block is based on a block-level element, this property is an offset from the padding edge of that element. :DEL] C.5.31 Section 9.5 Floats [2008-08-19] Positioned descendants of a float are in the stacking context of the float's parent. Add âpositioned elements andâ to [â¦] except that any [INS: positioned elements and :INS] elements that actually create new stacking contexts take part in the float's parent's stacking context. Same change in Section 9.9 Layered presentation: [â¦] except that any [INS: positioned elements and :INS] any elements that actually create new stacking contexts take part in the parent stacking context.â C.5.32 Section 9.5 Floats [2008-12-02] Remove â'sâ that may be misinterpreted: âthe float's parent[DEL: 's :DEL] stacking context.â C.5.33 Section 9.5.2 Controlling flow next to floats: the 'clear' property [2009-02-02] Add an example of negative clearance after the first note. C.5.34 Section 9.6.1 Fixed positioning [2008-11-03] Added: [INS: Boxes with fixed position that are larger than the page box are clipped. Parts of the fixed position box that are not visible in the initial containing block will not print. :INS] C.5.35 Section 9.9.1 Specifying the stack level: the 'z-index' property [2008-12-02] The list of stacking levels is ambiguous: relatively positioned elements could fall under items 3/4/5 or under item 6. Meant is item 6, so exclude them from 3/4/5 as follows: 1. the background and borders of the element forming the stacking context. 2. the stacking contexts of descendants with negative stack levels. 3. a stacking level containing in-flow non-inline-level [INS: non-positioned :INS] descendants. 4. a stacking level for [INS: non-positioned :INS] floats and their contents. 5. a stacking level for in-flow inline-level [INS: non-positioned :INS] descendants. 6. a stacking level for positioned descendants with 'z-index: auto', and any descendant stacking contexts with 'z-index: 0'. 7. the stacking contexts of descendants with positive stack levels. C.5.36 Section 10.1 Definition of "containing block" [2009-02-02] Rephrase first bullet point to make easier to read: [DEL: The containing block in which the root element lives is a rectangle with the dimensions of the viewport, anchored at the canvas origin for continuous media, and the page area for paged media. This containing block is called the initial containing block. :DEL] [INS: The containing block in which the root element lives is a rectangle called the initial containing block. For continuous media, it has the dimensions of the viewport and is anchored at the canvas origin; it is the page area for paged media. :INS] C.5.37 Section 10.3 Calculating widths and margins [2009-04-15] The values of 'left' and 'right' are only determined by section 9.4.3 in the case of relatively positioned elements: For Points 1-6 and 9-10, the values of 'left' and 'right' [DEL: used for layout :DEL] [INS: in the case of relatively positioned elements :INS] are determined by the rules in section 9.4.3. C.5.38 Section 10.3.1 Inline, non-replaced elements [2009-04-15] The only case in which 'left' or 'right' can be 'auto' is when the element is statically positioned. In that case 'left' and 'right are ignored and there is thus no need to determine a used value: A computed value of 'auto' for [DEL: 'left', 'right', :DEL] 'margin-left' or 'margin-right' becomes a used value of '0'. C.5.39 Section 10.3.2 Inline, replaced elements [2007-11-14] Add the following paragraph: [INS: Otherwise, if 'width' has a computed value of 'auto', and the element has an intrinsic width, then that intrinsic width is the used value of 'width'. :INS] just before the paragraph beginning "Otherwise, if 'width' has a computed value of 'auto', but none of the conditions above are met, [â¦]". C.5.40 Section 10.3.2 Inline, replaced elements [2008-03-05] Change the last paragraph as follows: If it does, [DEL: then a percentage intrinsic width on that element cannot be resolved and the element is assumed to have no intrinsic width :DEL] [INS: then the resulting layout is undefined in CSS2.1 :INS] . C.5.41 Section 10.3.3 Block-level, non-replaced elements in normal flow [2008-03-05] Scrollbar widths are no longer included in the containing block width. Remove scrollbar width from: 'margin-left' + 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' + 'margin-right' [DEL: + scrollbar width (if any) :DEL] = width of containing block and from: If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' [DEL: + scrollbar width (if any) :DEL] [...] and remove the paragraph: [DEL: The "scrollbar width" value is only relevant if the user agent uses a scrollbar as its scrolling mechanism. See the definition of the 'overflow' property. :DEL] C.5.42 Section 10.3.7 Absolutely positioned, non-replaced elements [2008-03-05] Scrollbar widths are no longer included in the containing block width. Remove scrollbar width from: 'left' + 'margin-left' + 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' + 'margin-right' + 'right' [DEL: + scrollbar width (if any) :DEL] = width of containing block and remove the paragraph: [DEL: The "scrollbar width" value is only relevant if the user agent uses a scrollbar as its scrolling mechanism. See the definition of the 'overflow' property. :DEL] C.5.43 Section 10.3.7 Absolutely positioned, non-replaced elements [2008-03-05] Add the following definition. [2008-08-19] Add the following note to that definition. [INS: The static-position containing block is the containing block of a hypothetical box that would have been the first box of the element if its specified 'position' property had been 'static' and its 'float' had been 'none'. (Note that due to the rules in section 9.7 this hypothetical calculation might require also assuming a different computed value for 'display'.) :INS] And change which 'direction' property is used as follows (two occurrences): [...] if the 'direction' property of the [INS: element establishing the static-position :INS] containing block is [...] C.5.44 Section 10.3.8 Absolutely positioned, replaced elements [2008-03-05] Change bullet 2 as follows: [...] if [INS: the :INS] 'direction' [INS: property :INS] of the [INS: element establishing the static-position :INS] containing block is [...] C.5.45 Section 10.3.8 Absolutely positioned, replaced elements [2008-03-05] Clarification. Replace [DEL: This situation is similar to the previous one, except that the element has an intrinsic width. The sequence of substitutions is now: :DEL] by [INS: In this case, section 10.3.7 applies up through and including the constraint equation, but the rest of section 10.3.7 is replaced by the following rules: :INS] C.5.46 Section 10.3.8 Absolutely positioned, replaced elements [2008-04-07] Clarified that margins are not calculated as for inline elements. C.5.47 Section 10.5 Content height: the 'height' property Under â ,â add the same note as under â ,â in section 10.2 (âContent width: the 'width' propertyâ). C.5.48 Section 10.6.2 Inline replaced elements [â¦] [2007-11-14] Add the following paragraph: [INS: Otherwise, if 'height' has a computed value of 'auto', and the element has an intrinsic height, then that intrinsic height is the used value of 'height'. :INS] just before the paragraph beginning "Otherwise, if 'height' has a computed value of 'auto', but none of the conditions above are met [â¦]". C.5.49 Section 10.6.4 Absolutely positioned, non-replaced elements [2008-11-26] The static position is determined considering neither float nor clear. Add this: [â¦] and its specified 'float' had been 'none' [INS: and 'clear' had been 'none' :INS] . C.5.50 Section 10.6.5 Absolutely positioned, replaced elements [2008-04-07] Clarified that margins are not calculated as for inline elements. C.5.51 Section 10.8.1 Leading and half-leading [2007-11-14] In the Note under 'vertical-align', remove "slightly" from "Values of this property have [DEL: slightly :DEL] different meanings in the context of tables." C.5.52 Section 11.1.1 Overflow: the 'overflow' property [2008-03-05] Scrollbar widths are no longer included in the containing block width. Replace [DEL: The space taken up by the scrollbars affects the computation of the dimensions in the rendering model. :DEL] by [INS: Any space taken up by the scrollbars should be taken out of (subtracted from the dimensions of) the containing block formed by the element with the scrollbars. :INS] [2008-11-03] 'Overflow' on BODY is special not only in HTML but also in XHTML. Change the sentence â[DEL: HTML UAs must instead apply the 'overflow' property from the BODY element to the viewport, if the value on the HTML element is 'visible'. :DEL] â to: [INS: When the root element is an HTML "HTML" element or an XHTML "html" element, and that element has an HTML "BODY" element or an XHTML "body" element as a child, user agents must instead apply the 'overflow' property from the first such child element to the viewport, if the value on the root element is 'visible'. :INS] C.5.53 Section 11.1.2 Clipping: the 'clip' property [2008-03-05] Insert "(but not a combination)" in "User agents must support separation with commas, but may also support separation without commas [INS: (but not a combination) :INS] ". C.5.54 Section 12.2 The 'content' property [2009-04-15] (And also in section 12.4:) certain keywords, in particular 'none', 'inherit' and 'initial' (the latter being reserved for future use) cannot be used as names for counters. C.5.55 Section 12.4.2 Counter styles [2008-03-05] Error in example. Replace hebrew by lower-greek: BLOCKQUOTE:after { content: " [" counter(bq, [DEL: hebrew :DEL] [INS: lower-gre ek :INS] ) "]" } C.5.56 Section 12.5 Lists [2008-12-01] Change âinâ to âwith respect toâ in The list properties describe basic visual formatting of lists: they allow style sheets to specify the marker type (image, glyph, or number), and the marker position [DEL: in :DEL] [INS: with respect to :INS] the principal box (outside it or within it before content). because the marker is, as the rest of the sentence itself makes clear, not necessarily in the principal box. C.5.57 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2008-04-07] The size of list style markers without an intrinsic size is now defined. C.5.58 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2008-12-01] CSS 2.1 does not specify the position of the list item marker, but does require it to be on the left or right of the content. Also, the marker is not affected by 'overflow', but may influence the height of the principal box. Add to the definition of 'outside': [INS: ⦠but does require that for list items whose 'direction' property is 'ltr' the marker box be on the left side of the content and for elements whose 'direction' property is 'rtl' the marker box be on the right side of the content. 'Overflow' on the element does not clip the marker box. The marker box is fixed with respect to the principal block box's border and does not scroll with the principal block box's content. The size or contents of the marker box may affect the height of the principal block box and/or the height of its first line box, and in some cases may cause the creation of a new line box. Note: This interaction may be more precisely defined in a future level of CSS. :INS] C.5.59 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2009-04-015] Meaning of 'none' for 'list-style' was only defined by an example. C.5.60 Section 13.2 Page boxes: the @page rule [2008-08-19] Add rules for drawing canvas to: * The page area. The page area includes the boxes laid out on that page. The edges of the first page area establish the rectangle that is the initial containing block of the document. [INS: The canvas background is painted within and covers the page area. :INS] * The margin area, which surrounds the page area. [INS: The page margin area is transparent. :INS] C.5.61 Section 13.2.1.1 Rendering page boxes that do not fit a target sheet [2009-02-02] Remove sections 13.2.1.1 and 13.2.1.2. (The described situations cannot occur in CSS 2.1, because CSS 2.1 does not have a 'size' property.) C.5.62 Section 13.2.3 Content outside the page box [2008-11-03] Clarified what locations are inconvenient for printing: When formatting content in the page model, some content may end up outside the [INS: current :INS] page box. For example, an element whose 'white-space' property has the value 'pre' may generate a box that is wider than the page box. [INS: As another example, :INS] when boxes are positioned absolutely [INS: or relatively :INS] , they may end up in âinconvenientâ locations. For example, images may be placed on the edge of the page box or 100,000 meters below the page box. C.5.63 Section 13.3.1 Page break properties: 'page-break-before', 'page-break-after', 'page-break-inside' [2008-04-30] The 'page-break-inside' property no longer inherits. C.5.64 Section 13.3.1 Page break properties: 'page-break-before', 'page-break-after', 'page-break-inside' [2008-12-01] UAs may apply 'page-break-before', 'page-break-after' and 'page-break-inside' to other elements than block-level ones. C.5.65 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' [2009-02-02] âParagraphâ is not a defined term. Change [DEL: of a paragraph :DEL] to [INS: in a block element :INS] (twice). C.5.66 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' [2009-04-15] 'Widows' and 'orphans' only accept positive values. C.5.67 Section 13.3.3 Allowed page breaks [2008-04-30] The 'page-break-inside' property of all ancestors is checked for page-breaking restrictions, not just that of the breakpoint's parent. C.5.68 Section 13.3.3 Allowed page breaks [2009-02-02] Remove possible confusion: Rule D: In addition, breaking at (2) is allowed only if the 'page-break-inside' property of [INS: the element and :INS] all [INS: its :INS] ancestors is 'auto'. C.5.69 Section 13.3.3 Allowed page breaks [2009-02-02] Top margins do not disappear at a page break that is forced by a 'page-break-after' or 'page-break-before'. Correct the first bullet to: When an [INS: unforced :INS] page break occurs here, the used values of the relevant 'margin-top' and 'margin-bottom' properties are set to '0'. [INS: When a forced page break occurs here, the used value of the relevant 'margin-bottom' property is set to '0'; the relevant 'margin-top' used value may either be set to '0' or retained. :INS] And add the following note: [INS: Note: It is expected that CSS3 will specify that the relevant 'margin-top' applies (i.e., is not set to '0') after a forced page break. :INS] C.5.70 Section 13.3.5 "Best" page breaks [2009-02-02] Remove the advice to user agents to avoid breaking inside elements with borders, inside tables or inside floating elements; add the advice to avoid breaking inside replaced elements. C.5.71 Section 14.2 The background [2008-11-03] The 'background' property is special on BODY not only in HTML but also in XHTML. C.5.72 Section 14.2 The background [2009-04-15] The whole 'background' property is used for the canvas, not just the color and the image: For documents whose root element is an HTML "HTML" element or an XHTML "html" element that has computed values of 'transparent' for 'background-color' and 'none' for 'background-image', user agents must instead use the computed value of [DEL: those :DEL] [INS: the background :INS] properties from that element's first HTML "BODY" element or XHTML "body" element child [â¦] C.5.73 Section 14.2.1 Background properties: 'background-color', 'background-image', 'background-repeat', 'background-attachment', 'background-position', and 'background' [2008-04-07] The size of background images without an intrinsic size is now defined. C.5.74 Section 15.6 Font boldness: the 'font-weight' property [2008-11-26] Remove incorrect text: * 'bolder' selects the next weight that is assigned to a font that is darker than the inherited one. [DEL: If there is no such weight, it simply results in the next darker numerical value (and the font remains unchanged), unless the inherited value was '900' in which case the resulting weight is also '900'. :DEL] * 'lighter' is similar, but works in the opposite direction: it selects the next lighter keyword with a different font from the inherited one, [DEL: unless there is no such font, in which case it selects the next lighter numerical value (and keeps the font unchanged) :DEL] . and: [DEL: The computed value of "font-weight" is either: :DEL] * [DEL: one of the legal number values, or :DEL] * [DEL: one of the legal number values combined with one or more of the relative values (bolder or lighter). This type of computed values is necessary to use when the font in question does not have all weight variations that are needed. :DEL] And instead add this note: [INS: Note: A set of nested elements that mix 'bolder' and 'lighter' will give unpredictable results depending on the UA, OS, and font availability. This behavior will be more precisely defined in CSS3. :INS] C.5.75 Section 16.6 Whitespace: the 'white-space' property [2008-08-19] Remove rules about generated text from: The following examples show what whitespace behavior is expected from the PRE and P elements, the ânowrapâ attribute in HTML, [DEL: and in generated content :DEL] . pre { white-space: pre } p { white-space: normal } td[nowrap] { white-space: nowrap } [DEL: :before,:after { white-space: pre-line } :DEL] C.5.76 Section 16.6.1 The 'white-space' processing model [2009-02-02] Collapsing of white space does not remove any line breaking opportunities. Add the following clarification: Then, the entire block is rendered. Inlines are laid out, taking bidi reordering into account, and wrapping as specified by the 'white-space' property. [INS: When wrapping, line breaking opportunities are determined based on the text prior to the white space collapsing steps above. :INS] C.5.77 Section 17.2.1 Anonymous table objects [2007-11-14] Spelling error: "boxes[DEL: s :DEL] ". C.5.78 Section 17.2.1 Anonymous table objects [2008-10-13] Added new rule after bullet 4: [INS: 5. If a child T of a 'table', 'inline-table', 'table-row-group', 'table-header-group', 'table-footer-group', or 'table-row' box is an anonymous inline box that contains only white space, then it is treated as if it has 'display: none'. :INS] C.5.79 Section 17.4 Tables in the visual formatting model [2009-02-02] The anonymous block containing the table and its caption establishes a block formatting context: The anonymous box is a 'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level [DEL: except that this block is never considered as a block for 'run-in' interaction, and that :DEL] [INS: The anonymous box establishes a block formatting context. :INS] The table box (not the anonymous box) is used when doing baseline vertical alignment for an 'inline-table'. The diagram now shows the caption's margins inside the anonymous box. C.5.80 Section 17.5.4 Horizontal alignment in a column [2008-04-07] Clarification: The horizontal alignment of a cell's [INS: inline :INS] content within a cell box [DEL: is :DEL] [INS: can be :INS] specified [DEL: with the 'text-align' property :DEL] [INS: by the value of the 'text-align' property on the cell :INS] . C.5.81 Section 18.1 Cursors: the 'cursor' property [2008-04-07] The size of cursors without an intrinsic size is now defined. C.5.82 Section B.2 Informative references [2007-11-14] Spelling error: change "[DEL: ? :DEL] lik" to "[INS: à :INS] elik" (2Ã). C.5.83 Appendix D. Default style sheet for HTML 4 [2008-08-19] Replace br:before { content: "\A" } :before, :after { white-space: pre-line } with br:before { content: "\A"; white-space: pre-line } C.5.84 Appendix D. Default style sheet for HTML 4 [2008-08-19] Add tr to: td, th[INS: , tr :INS] { vertical-align: inherit } C.5.85 Section E.2 Painting order [2007-11-14] Replace "but any descendants which actually create a new stacking context" by "but any [INS: positioned descendants and :INS] descendants which actually create a new stacking context". C.5.86 Appendix G. Grammar of CSS 2.1 [2007-09-27] Change the last "S" in the grammar rule for "combinator" to "S+": combinator : PLUS S* | GREATER S* | S[INS: + :INS] and remove the rule [DEL: {s}+\/\*[^*]*\*+([^/*][^*]*\*+)*\/ {unput(' '); /*replace by space*/} :DE L] in the tokenizer. The resulting language is the same, but the grammar is easier to read and relies less on specific notations of Flex. C.5.87 Section G.1 Grammar [2007-09-27] Changes to remove ambiguity with respect to the S token and avoid nullable non-terminals. C.5.88 Section G.2 Lexical scanner [2007-09-27] Change the tokenizer rule [DEL: @{C}{H}{A}{R}{S}{E}{T} :DEL] {return CHARSET_SYM;} to [INS: "@charset " :INS] {return CHARSET_SYM;} The @charset must be in lowercase and must have a space after it (as defined in section 4.4 CSS style sheet representation). C.5.89 Section G.2 Lexical scanner [2008-03-05] Change the tokenizer rules [DEL: "url :DEL] ("{w}{string}{w}")" {return URI;} [DEL: "url :DEL] ("{w}{url}{w}")" {return URI;} to [INS: {U}{R}{L}" :INS] ("{w}{string}{w}")" {return URI;} [INS: {U}{R}{L}" :INS] ("{w}{url}{w}")" {return URI;} C.5.90 Section G.2 Lexical scanner [2008-04-07] The definition of the macro âOâ is wrong. The letters O and o can be written with hexadecimal escapes as â\4fâ and â\6fâ respectively (not as â\51â and â\71â). The macro should therefore be O o|\\0{0,4}(4f|6f)(\r\n|[ \t\r\n\f])?|\\o C.5.91 Section G.2 Lexical scanner âThe two occurrences of "\377"â¦â: There is in fact only one occurrence. C.5.92 Appendix I. Index Add a TITLE attribute to all links and which is equal to the lemma. C.6 Errata since the Candidate Recommendation of April 2009 These are the errata for CSS level 2 revision 1, CR version of 23 April 2009. These corrections have the status of a draft. C.6.1 Section 4.2 Rules for handling parsing errors [2009-08-06] Clarified the rules for ignoring invalid at-keywords: Invalid at-keywords. User agents must ignore an invalid at-keyword together with everything following it, [INS: up to the end of the block that contains the invalid at-keyword, or :INS] up to and including the next semicolon (;), [INS: or up to and including :INS] the next block ({...}), [DEL: or the end of the block (}) that contains the invalid at-keyword, :DEL] whichever comes first. C.6.2 Section 13.3.3 Allowed page breaks [2009-08-06] Page breaks are also allowed when there is a gap after the last content of a block. Added the following to the first list: 3. Between the content edge of a block box and the outer edges of its child content (margin edges of block-level children or line box edges for inline-level children) if there is a (non-zero) gap between them. C.6.3 Section 15.3 Font family: the 'font-family' property [2009-08-31] The list of keywords in â(e.g., 'initial', 'inherit', 'default', 'serif', 'sans-serif', 'monospace', 'fantasy', and 'cursive')â isn't an example, but is in fact the complete and normative list. C.6.4 Section 15.3.1.1 serif [2009-08-31] Spelling errors in font names. The correct names are âExcelsior Cyrillic Uprightâ and âER Bukinist.â C.6.5 Section 15.7 Font size: the 'font-size' property [2009-08-31] The two notes âNote: implementation experience has demonstratedâ¦â and âNote 2. In CSS1, the suggested scaling factor⦠say essentially the same thing. They are replaced by a single note: Note 2. In CSS1, the suggested scaling factor between adjacent indexes was 1.5, which user experience proved to be too large. In CSS2, the suggested scaling factor for a computer screen between adjacent indexes was 1.2, which still created issues for the small sizes. Implementation experience has demonstrated that a fixed ratio between adjacent absolute-size keywords is problematic, and this specification does not recommend such a fixed ratio. C.6.6 Section 17.5.2.1 Fixed table layout [2009-05-20] UAs may render extra columns if there are unexpected columns in later rows of a 'fixed' table layout. In that case, the width of the columns and of the table is undefined. C.6.7 Section 17.5.3 Table height layout [2009-08-06] Replaced â[DEL: Percentage heights on table cells, table rows, and table row groups compute to 'auto' :DEL] by [INS: CSS 2.1 does not define how the height of table cells and table rows is calculated when their height is specified using percentage values. CSS 2.1 does not define the meaning of 'height' on row groups. :INS] C.6.8 Appendix G. Grammar of CSS 2.1 [2009-08-06] Removed ambiguities from the grammar. (The ambiguities only affected spaces and were harmless.) C.7 Errata since the Candidate Recommendation of September 2009 These are the errata for CSS level 2 revision 1, CR version of 8 September 2009. These corrections have the status of a draft. C.7.1 Section 1.4.2.1 Value [2010-08-06] (Also in various other sections throughout the specification.) Distinguished all cases where the word value referred to a whole property value from where it referred to only part of such a value (such as a component in a comma-separated list). The former is now property value, the latter component value. C.7.2 Section 3.1 Definitions [2010-04-19] Add a clarification to the definition of replaced element: [INS: The content of replaced elements is not considered in the CSS rendering model. :INS] (Previously, the definition only said that the content was âoutside the scope of CSS.â) C.7.3 Section 4.1.1 Tokenization [2010-04-19] The definition of âidentifierâ in 4.1.3 (2nd bullet) and in the grammar were contradictory w.r.t. whether no-break space (U+00A0) was allowed in identifiers or not. Change the text in 4.1.3 to allow no-break space: âcharacters [DEL: U+00A1 :DEL] [INS: U+00A0 :INS] and higher.â Also, change the macro ânonasciiâ in the token definition from â[DEL: [^\0-\177] :DEL] â to [INS: [^\0-\237] :INS] â. (When CSS was first written, Unicode didn't have code points U+0080 to U+009F, i.e., \200-\237 in octal.) C.7.4 Section 4.1.1 Tokenization [2010-09-29] The tokenizer has been modified so that it can be implemented as a state machine without back-up (e.g., with Lex). This changes the meaning of an input of the form âurl(â¦(â¦)â¦)â, i.e., input that starts like a URI token but then contains a parenthesis (which is not allowed in a URI token). Previously, such input was re-parsed to yield a FUNCTION token followed by other things; now it yields a BAD_URI token. Given that CSS has never used a FUNCTION token of the form âurl(â this should not affect any existing CSS style sheets. A non-normative section has been added to appendix G with an explanation of how to make a tokenizer without back-up. C.7.5 Section 4.1.1 Tokenization [2010-09-29] The definition of the URI token was ambiguous: it allowed a backslash to be either parsed on its own or as part of an escape. A backslash in a URI token must always be interpreted as part of an escape. C.7.6 Section 4.1.1 Tokenization [2010-09-29] Error handling for illegal tokens (braces, at-keywords, and SGML comment tokens) inside parenthesized expressions was not well defined. Change the production for âanyâ as follows any : [ IDENT | NUMBER | PERCENTAGE | DIMENSION | STRING | DELIM | URI | HASH | UNICODE-RANGE | INCLUDES | DASHMATCH | ':' | FUNCTION S* [INS: [ :INS] any[INS: |unsused] : INS] * ')' | '(' S* [INS: [ :INS] any[INS: |unused] :INS] * ')' | '[' S* [INS : [ :INS] any[INS: |unused] :INS] * ']' ] S*; [INS: unused : block | ATKEYWORD S* | ';' S* | CDO S* | CDC S*; :INS] and add the following explanation: [INS: The "unused" production is not used in CSS and will not be used by any future extension. It is included here only to help with error handling. (See 4.2 "Rules for handling parsing errors.") :INS] C.7.7 Section 4.1.2.2 Informative Historical Notes [2010-04-19] Add â-tc-â to the list of existing vendor prefixes. C.7.8 Section 4.1.3 Characters and case [2010-08-06] The handling of a backslash before a newline or at the end of a file is no longer undefined: it is parsed as a DELIM. C.7.9 Section 4.1.3 Characters and case [2010-08-06] Make text and formal grammar the same: In CSS, identifiers [â¦]; they cannot start with a digit, [INS: two hyphens, :INS] or a hyphen followed by a digit. C.7.10 Section 4.1.8 Declarations and properties [2010-05-12] Remove â2.1â from Every CSS [DEL: 2.1 :DEL] property has its own syntactic and semantic restrictions C.7.11 Section 4.2 Rules for handling parsing errors [2010-07-07] Clarify that the fifth bullet only applies to at-rules. (At-keywords in other constructs are already handled in the preceding bullets.) * [DEL: Invalid at-keywords :DEL] [INS: At-rules with unknown at-keywords :INS] . User agents must ignore⦠C.7.12 Section 4.3.2 Lengths [2010-04-19] Make explicit that 'ex', when used in the 'font-size' property, refers to the parent element's 'ex' (just as 'em' refers to the parent's 'em' in that case.) C.7.13 Section 4.3.2 Lengths [2010-10-28] A UA must now either display absolute lengths (cm, in, pt, etc.) at their real size or make px align with device pixel boundaries near the 0.0213 degrees viewing angle, but not both. In either case, 3px must equal 4pt. (Until now, authors could use absolute lengths for physical sizes and px for aligning to device pixels, but couldn't know the number of pt in a px, except in combination with Media Queries. Authors can no longer choose between absolute or device-related units, but can use px and pt interchangeably. This should only affect relatively low-resolution devices: above 300 dots per inch, the maximum error is about 16%.) C.7.14 Section 4.3.4 URLs and URIs [2010-05-12] Commas do not have to be escaped in tokens: Some characters appearing in an unquoted URI, such as parentheses, [DEL: commas, :DEL] white space characters, single quotes (') and double quotes ("), must be escaped C.7.15 Section 4.3.4 URLs and URIs [2010-04-21] Describe in English what was only expressed through the grammar: [INS: Note. Since URIs may contain characters that would otherwise be used as delimiters in CSS, the entire URI value must be treated as a single unit by the tokenizer and normal tokenization behavior does not apply within a URI value. Therefore comments are not allowed within a URI value. :INS] C.7.16 Section 5.8.2 Default attribute values in DTDs [2010-09-29] Clarify what is meant by âis not requiredâ: More precisely, a UA [INS: may, but :INS] is not required to[INS: , :INS] read an "external subset" of the DTD but is required to look for default attribute values in the document's "internal subset." (See [XML10] for definitions of these subsets.) [INS: Depending on the UA, a default attribute value defined in the external subset of the DTD might or might not appear in the document tree. :INS] A UA that recognizes an XML namespace [XMLNAMESPACES] [INS: may, but :INS] is not required to[INS: , :INS] use its knowledge of that namespace to treat default attribute values as if they were present in the document. (E.g., an XHTML UA is not required to use its built-in knowledge of the XHTML DTD.) and: the first rule [DEL: will :DEL] [INS: might :INS] not match elements whose "notation" attribute is set by default, i.e., not set explicitly. To catch all cases, the attribute selector for the default value must be dropped: C.7.17 Section 5.11.4 The language pseudo-class: :lang [2010-08-06] The argument of ':lang()' is only case-insensitive for characters in ASCII. C.7.18 Section 5.12 Pseudo-elements [2010-08-06] Clarify that pseudo-elements behave like elements for the aspects not explicitly mentioned: [INS: Pseudo-elements behave just like real elements in CSS with the exceptions described below and elsewhere. :INS] C.7.19 Section 5.12.1 The :first-line pseudo-element [2010-08-24] More consistent use of âblockâ and âblock-level.â Change: The :first-line pseudo-element can only be attached to a [DEL: block-level element, inline-block, table-caption or a table-cell :DEL] [INS: block container element :INS] . C.7.20 Section 5.12.2 The :first-letter pseudo-element [2010-08-24] More consistent use of âblockâ and âblock-level.â Change: The :first-letter pseudo-element applies to [DEL: block, list-item, table-cell, table-caption and inline-block elements :DEL] [INS: block container elements :INS] . C.7.21 Section 6.2 Inheritance [2010-08-06] Add a note that, because it follows the document tree, inheritance is not intercepted by anonymous boxes C.7.22 Section 6.4.4 Precedence of non-CSS presentational hints [2010-10-05] Give other languages than HTML (such as SVG) the possibility to define certain attributes as âpresentational attributesâ: For other languages, all document language-based styling [DEL: should be handled in the user agent style sheet :DEL] [INS: must be translated to the corresponding CSS and either enter the cascade at the user agent level or, as with HTML presentational hints, be treated as author level rules with a specificity of zero placed at the start of the author style sheet :INS] . C.7.23 Section 7.3 Recognized media types [2010-09-08] Clarify what is ignored. Change: @media and @import rules with unknown media types [INS: (that are nonetheless valid identifiers) :INS] are treated as if the unknown media types are not present. [INS: If an @media/@import rule contains a malformed media type (not an identifier) then the statement is invalid. :INS] [INS: Note: Media Queries supercedes this error handling. :INS] C.7.24 Section 8.3.1 Collapsing margins [2010-05-12] Simplify/clarify text: An element that has [DEL: had :DEL] clearance [DEL: applied to it :DEL] never collapses and: When an element's own margins collapse, and that element has [DEL: had :DEL] clearance [DEL: applied to it :DEL] C.7.25 Section 8.3.1 Collapsing margins [2010-08-24] More consistent use of âblock boxâ vs âblock-level element.â Include table captions in the set of block-level elements. See also changes to 9.2.1 and to 9.2.1.1. Two or more adjoining vertical margins of block[INS: -level :INS] boxes in the normal flow collapse. and The top margin of an in-flow [DEL: block-level element :DEL] [INS: block box :INS] is adjoining to its first in-flow block-level child's top margin and The bottom margin of an in-flow [DEL: block-level element :DEL] [INS: block box :INS] with a 'height' of 'auto' C.7.26 Section 9.2.1 Block-level elements and block boxes [2010-08-24] Define the term âblock-level elementâ more precisely. Also define auxiliary terms âblock container boxâ and âblock boxâ: More consistent use of block box vs block-level element in section 9.2.1.1. See also changes to section 8.3.1 and 9.4. C.7.27 Section 9.2.1.1 Anonymous block boxes [2010-05-12] The example has invalid HTML mark-up. Change it to use P and SPAN elements instead of BODY and P. [2010-08-06] Also clarify that âblock boxâ only refers to boxes in the same flow. C.7.28 Section 9.2.1.1 Anonymous block boxes [2010-09-29] Percentage values that refer to dimensions of parent boxes ignore any intervening anonymous boxes. Add this paragraph: [INS: Anonymous block boxes are ignored when resolving percentage values that would refer to it: the closest non-anonymous ancestor box is used instead. For example, if the child of the anonymous block box inside the DIV above needs to know the height of its containing block to resolve a percentage height, then it will use the height of the containing block formed by the DIV, not of the anonymous block box. :INS] C.7.29 Section 9.2.1.1 Anonymous block boxes [2010-09-29] Clarify the wording: When an inline box contains an in-flow block box [â¦] When such an inline box is affected by relative positioning, the relative positioning also affects the block-level box [INS: contained in the block box :INS] . C.7.30 Section 9.2.1.1 Anonymous block boxes [2010-10-13] Clarify that an inline box that is broken around a block-level box is always broken into two pieces, even if one or both are empty: When an inline box contains an in-flow block-level box, the inline box (and its inline ancestors within the same line box) are broken around the block-level box[INS: , dividing the inline box into two pieces, even if either side is empty. :INS] . C.7.31 Section 9.2.2 Inline-level elements and inline boxes [2010-08-24] Better define the term âinline-level element/boxâ and define the auxiliary terms âinline boxâ and âatomic inline-level box.â C.7.32 Section 9.2.3 Run-in boxes [2010-04-19] Make the definition of 'run-in' more precise: [DEL: A run-in box behaves as follows: :DEL] 1. [DEL: If the run-in box contains a block box, the run-in box becomes a block box. :DEL] 2. [DEL: If a sibling block box (that does not float and is not absolutely positioned) follows the run-in box, the run-in box becomes the first inline box of the block box. A run-in cannot run in to a block that already starts with a run-in or that itself is a run-in. :DEL] 3. [DEL: Otherwise, the run-in box becomes a block box. :DEL] [INS: A run-in element (or pseudo-element) A behaves as follows: :INS] 1. [INS: If A has any children that inhibit run-in behavior (see below), then A is rendered as if it had 'display: block'. :INS] 2. [INS: Let B be the first of A's following siblings that is neither floating nor absolutely positioned nor has 'display: none'. If B exists and has a specified value for 'display' of 'block' or 'list-item' and is not replaced, then A is rendered as an 'inline' element at the start of B's principal box. Note: A is rendered before B's ':before' pseudo-element, if any. See 12.1. :INS] 3. [INS: Otherwise, A is rendered as if it had 'display: block'. :INS] [INS: In the above, "siblings" and "children" include both normal elements and :before/:after pseudo-elements. :INS] [INS: An element or pseudo-element C inhibits run-in behavior if one of the following is true. (Note that the definition is recursive.) :INS] 1. [INS: C is not floating and not absolutely positioned and the computed value of its 'display' is one of 'block', 'list-item', 'table' or 'run-in'. :INS] 2. [INS: C has a computed value for 'display' of 'inline' and it has one or more children that inhibit run-in behavior. (Where "children" includes both normal elements and :before/:after pseudo-elements.) :INS] It remains undefined how 'run-in' and ':first-line' interact: [INS: It is undefined in CSS 2.1 if a run-in inherits from a ':first-line' pseudo-element. :INS] C.7.33 Section 9.2.4 The 'display' property [2010-08-06] Use the same terminology as in chapter 12: list-item This value causes an element (e.g., LI in HTML) to generate a principal block box and a [DEL: list-item inline :DEL] [INS: marker :INS] box. C.7.34 Section 9.2.4 The 'display' property [2010-08-24] More consistent use of âinline-level.â inline-block This value causes an element to generate [DEL: a block box, which itself is flowed as a single inline box, similar to a replaced element :DEL] [INS: an inline-level block container :INS] . The inside of an inline-block is formatted as a block box, and the element itself is formatted as an [DEL: inline replaced element :DEL] [INS: an atomic inline-level box :INS] . C.7.35 Section 9.3 Positioning schemes [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â 1. Normal flow. In CSS 2.1, normal flow includes block formatting of block[INS: -level :INS] boxes, inline formatting of inline[INS: -level :INS] boxes, relative positioning of block[INS: -level :INS] [DEL: or :DEL] [INS: and :INS] inline[INS: -level :INS] boxes, and [DEL: positioning :DEL] [INS: formatting :INS] of run-in boxes. C.7.36 Section 9.4 Normal flow [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â Boxes in the normal flow belong to a formatting context, which may be block or inline, but not both simultaneously. Block[INS: -level :INS] boxes participate in a block formatting context. Inline[INS: -level :INS] boxes participate in an inline formatting context. In 9.4.1: Floats, absolutely positioned elements, [DEL: inline-blocks, table-cells, table-captions, and elements with 'overflow' other than 'visible' (except when that value has been propagated to the viewport) establish new block formatting contexts :DEL] [INS: block containers (such as inline-blocks, table-cells, and table-captions) that are not block boxes, and block boxes with 'overflow' other than 'visible' :INS] . In a block formatting context, boxes are laid out one after the other, vertically, beginning at the top of a containing block. The vertical distance between two sibling boxes is determined by the 'margin' properties. Vertical margins between adjacent block[INS: -level :INS] boxes in a block formatting context collapse. In 9.4.2: [â¦] When several inline[INS: -level :INS] boxes cannot fit horizontally within a single line box, they are distributed among two or more vertically-stacked line boxes. When the total width of the inline[INS: -level :INS] boxes on a line [â¦]is less than the width of the line box containing them, their horizontal distribution within the line box is determined by the 'text-align' property. If that property has the value 'justify', the user agent may stretch spaces and words in inline boxes ([DEL: except for :DEL] [INS: but not :INS] inline-table and inline-block boxes) as well. C.7.37 Section 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' [2010-07-19] If 'top', 'right', 'bottom' or 'left' is specified as 'auto', the used value rather than the computed value is set to the negative of the opposite side. For all four, change: Computed value: [DEL: for 'position:relative', see section Relative Positioning. :DEL] For 'position:static', 'auto'. Otherwise: if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'. And in section 9.4.3: [â¦] Since boxes are not split or stretched as a result of 'left' or 'right', the [DEL: computed :DEL] [INS: used :INS] values are always: left = -right. If both 'left' and 'right' are 'auto' (their initial values), the [DEL: computed :DEL] [INS: used :INS] values are '0' (i.e., the boxes stay in their original position). If 'left' is 'auto', its [DEL: computed :DEL] [INS: used :INS] value is minus the value of 'right' (i.e., the boxes move to the left by the value of 'right'). If 'right' is specified as 'auto', its [DEL: computed :DEL] [INS: used :INS] value is minus the value of 'left'. [â¦] Since boxes are not split or stretched as a result of 'top' or 'bottom', the [DEL: computed :DEL] [INS: used :INS] values are always: top = -bottom. If both are 'auto', their [DEL: computed :DEL] [INS: used :INS] values are both '0'. If one of them is 'auto', it becomes the negative of the other. If neither is 'auto', 'bottom' is ignored (i.e., the [DEL: computed :DEL] [INS: used :INS] value of 'bottom' will be minus the value of 'top'). C.7.38 Section 9.5 Floats [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â [â¦] In other words, if inline[INS: -level :INS] boxes are placed on the line before a left float is encountered that fits in the remaining line box space, the left float is placed on that line, aligned with the top of the line box, and then the inline[INS: -level :INS] boxes already on the line are moved accordingly to the right of the float (the right being the other side of the left float) and vice versa for rtl and right floats. In 9.5.2: Values have the following meanings when applied to non-floating block[INS: -level :INS] boxes: C.7.39 Section 9.5 Floats [2010-10-25] Define exactly what it means for a line box to be next to a float: [â¦] However, line boxes created next to the float are shortened to make room for the margin box of the float. [INS: A line box is next to a float when there exists a vertical position that satisfies all of these four conditions: (a) at or below the top of the line box, (b) at or above the bottom of the line box, (c) below the top margin edge of the float, and (d) above the bottom margin edge of the float. :INS] [INS: Note: this means that floats with zero height or negative height do not move line boxes. :INS] C.7.40 Section 9.5.2 Controlling flow next to floats: the 'clear' property [2010-05-12] Clarify that 'clear' only introduces clearance above an element if necessary; and that clearance may have zero height. C.7.41 Section 9.5.2 Controlling flow next to floats: the 'clear' property [2010-10-13] Added an example of calculating clearance from two collapsing margins M1 and M2 and the height H of a float. C.7.42 Section 9.5.2 Controlling flow next to floats: the 'clear' property [2010-10-13] Clarify the language: Computing the clearance of an element on which 'clear' is set is done by first determining the hypothetical position of the element's top border edge within its parent block. [DEL: This position is determined after the top margin of the element has been collapsed with previous adjacent margins (including the top margin of the parent block). :DEL] [INS: This position where the actual top border edge would have been if the element had a non-zero top border and its 'clear' property had been 'none'. :INS] If this hypothetical position of the element's top border edge is not past the relevant floats, then clearance [DEL: must be :DEL] [INS: is introduced, and margins collapse according to the rules in 8.3.1. :INS] [INS: Then the amount of clearance is :INS] set to the greater of: 1. The amount necessary to place the border edge of the block even with the bottom outer edge of the lowest float that is to be cleared. 2. [DEL: The amount necessary to make the sum of the following equal to the distance to which these margins collapsed when the hypothetical position was calculated: :DEL] + [DEL: the margins collapsing above the clearance :DEL] + [DEL: the clearance itself :DEL] + [DEL: if the block's own margins collapse together: the block's top margin :DEL] + [DEL: if the block's own margins do not collapse together: the margins collapsing below the clearance :DEL] [INS: The amount necessary to place the top border edge of the block at its hypothetical position. :INS] C.7.43 Section 9.5.2 Controlling flow next to floats: the 'clear' property [2010-10-13] Correction: The hypothetical position is determined by assuming the box has a non-zero bottom border (see section 8.3.1): This position is where the actual top border edge would have been if the element had a non-zero [DEL: top :DEL] [INS: bottom :INS] border and its 'clear' property had been 'none'. C.7.44 Section 14.2.1 Background properties [2010-04-19] 'Fixed' backgrounds in paged media are positioned relative to the page box (and thus repeat on every page, just like 'fixed' elements). The position of fixed backgrounds in paged media was previously undefined. C.7.45 Section 9.9.1 Specifying the stack level: the 'z-index' property [2010-07-07] Some ambiguities in the description of stacking contexts are fixed and the description is clearly marked as non-normative. (Appendix E holds the normative description.) C.7.46 Section 9.10 Text direction: the 'direction' and 'unicode-bidi' properties [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â User agents that support bidirectional text must apply the Unicode bidirectional algorithm to every sequence of inline[INS: -level :INS] boxes uninterrupted by a forced line break or block boundary. This sequence forms the "paragraph" unit in the bidirectional algorithm. The paragraph embedding level is set according to the value of the 'direction' property of the containing block rather than by the heuristic given in steps P2 and P3 of the Unicode algorithm. [â¦] For the 'direction' property to affect reordering in inline[DEL: -level :DEL] elements, the 'unicode-bidi' property's value must be 'embed' or 'override'. [â¦] normal The element does not open an additional level of embedding with respect to the bidirectional algorithm. For inline[DEL: -level :DEL] elements, implicit reordering works across element boundaries. embed If the element is inline[DEL: -level :DEL] , this value opens an additional level of embedding with respect to the bidirectional algorithm. The direction of this embedding level is given by the 'direction' property. Inside the element, reordering is done implicitly. This corresponds to adding a LRE (U+202A; for 'direction: ltr') or RLE (U+202B; for 'direction: rtl') at the start of the element and a PDF (U+202C) at the end of the element. bidi-override For inline[DEL: -level :DEL] elements this creates an override. For [DEL: block-level, table-cell, table-caption, or inline-block :DEL] [INS: block container :INS] elements this creates an override for inline-level descendants not within another block container element. This means that inside the element, reordering is strictly in sequence according to the 'direction' property; the implicit part of the bidirectional algorithm is ignored. This corresponds to adding a LRO (U+202D; for 'direction: ltr') or RLO (U+202E; for 'direction: rtl') at the start of the element or at the start of each anonymous child block box, if any, and a PDF (U+202C) at the end of the element. The final order of characters in each [DEL: block-level element :DEL] [INS: block container :INS] is [â¦] C.7.47 Section 9.10 Text direction: the 'direction' and 'unicode-bidi' properties [2010-10-05] Add a reference to bidi class B in Unicode TR 9 to clarify what a âforced breakâ is in the context of the Unicode bidi algorithm: [â¦] inline-level boxes uninterrupted by a forced [DEL: line :DEL] [INS: (bidi class B) :INS] break or block boundary C.7.48 Section 9.10 Text direction: the 'direction' and 'unicode-bidi' properties [2010-10-25] clarify ânon-textual entitiesâ: In this process, [DEL: non-textual entities such as images :DEL] [INS: replaced elements with 'display: inline' (and replaced elements with 'display: run-in', when they generate inline-level boxes) :INS] are treated as neutral characters, unless their 'unicode-bidi' property has a value other than 'normal', in which case they are treated as strong characters in the 'direction' specified for the element. [INS: All other atomic inline-level boxes are treated as neutral characters always. :INS] C.7.49 Section 10.1 Definition of "containing block" [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â 1. [â¦] 2. For other elements, if the element's position is 'relative' or 'static', the containing block is formed by the content edge of the nearest [DEL: block-level, table cell or inline-block :DEL] [INS: block container :INS] ancestor box. 3. [â¦] 4. [â¦] 1. In the case that the ancestor is [DEL: inline-level :DEL] [INS: an inline box :INS] , the containing block depends on the 'direction' property of the ancestor: C.7.50 Section 10.2 Content width: the 'width' property [2010-05-12] The computed value of 'width' doesn't depend on whether the property applies or not: Computed value: the percentage or 'auto' as specified or the absolute length; [DEL: 'auto' if the property does not apply :DEL] C.7.51 Section 10.2 Content width: the 'width' property [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â This property specifies the content width of boxes [DEL: generated by block-level and replaced elements :DEL] . This property does not apply to non-replaced inline[DEL: -level :DEL] elements. C.7.52 Section 10.2 Content width: the 'width' property [2010-10-05] Remove unclear and redundant sentence: [DEL: The width of a replaced element's box is intrinsic and may be scaled by the user agent if the value of this property is different than 'auto'. :DEL] C.7.53 Section 10.5 Content height: the 'height' property [2010-05-12] The computed value of 'height' doesn't depend on whether the property applies or not: Computed value: the percentage or 'auto' (see prose under ) or the absolute length; [DEL: 'auto' if the property does not apply :DEL] C.7.54 Section 10.5 Content height: the 'height' property [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â This property specifies the content height of boxes [DEL: generated by block-level, inline-block and replaced elements :DEL] . This property does not apply to non-replaced inline[DEL: -level :DEL] elements. See the section on computing heights and margins for non-replaced inline elements for the rules used instead. C.7.55 Section 10.6.7 'Auto' heights for block formatting context roots [2010-08-06] Clarify âbottomâ and âprecedingâ: In certain cases (see [DEL: the preceding sections :DEL] [INS: e.g., sections 10.6.4 and 10.6.6 :INS] ), the height of an element that establishes a block formatting context is computed as follows: [â¦] In addition, if the element has any floating descendants whose bottom margin edge is below the [DEL: bottom :DEL] [INS: the element's bottom content edge :INS] , then the height is increased to include those edges. Only floats that are children of the element itself or of descendants in the normal flow are taken into account, e.g., floats inside absolutely positioned descendants or other floats are not. C.7.56 Section 10.7 Minimum and maximum heights: 'min-height' and 'max-height' [2010-10-26] The effect of 'min-height' and 'max-height' on table cells is still undefined in CSS: [INS: In CSS 2.1, the effect of 'min-height' and 'max-height' on tables, inline tables, table cells, table rows, and row groups is undefined. :INS] C.7.57 Section 10.8 Line height calculations: the 'line-height' and 'vertical-align' properties [2010-06-02] Clarifications to the calculation of the line boxes and the minimum line height ("strut"). Item 2 in the bulleted list is expanded and items 3 and 4 are merged, as follows: 1. The height of each inline box in the line box is calculated (see "Calculating heights and margins" and the 'line-height' property). 2. The inline boxes are aligned vertically according to their 'vertical-align' property. [INS: In case they are aligned 'top' or 'bottom', they must be aligned so as to minimize the line box height. If such boxes are tall enough, there are multiple solutions and CSS 2.1 does not define the position of the line box's baseline (i.e., the position of the strut, see below). :INS] 3. The line box height is the distance between the uppermost box top and the lowermost box bottom. [INS: (This includes the strut, as explained under 'line-height' below.) :INS] 4. [DEL: If the resulting height is smaller than the minimal height of line boxes for this block, as specified by the 'line-height' property, the height is increased to be that minimal height. :DEL] Furthermore, in 10.8.1, after the definition of âstrut,â clarify that the font determines the initial baseline: [INS: The height and depth of the font above and below the baseline are assumed to be metrics that are contained in the font. (For more details, see CSS level 3.) :INS] C.7.58 Section 10.8 Line height calculations: the 'line-height' and 'vertical-align' properties [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â As described in the section on inline formatting contexts, user agents flow inline[INS: -level :INS] boxes into a vertical stack of line boxes. The height of a line box is determined as follows: 1. The height of each inline[INS: -level :INS] box in the line box is calculated (see "Calculating heights and margins" and the 'line-height' property). 2. The inline[INS: -level :INS] boxes are aligned vertically according to their 'vertical-align' property. In 10.8.1: On a [DEL: block-level, table-cell, table-caption or inline-block :DEL] [INS: block container :INS] element whose content is composed of inline-level elements, 'line-height' specifies the minimal height of line boxes within the element. [â¦] On an inline[DEL: -level :DEL] element, 'line-height' specifies the height that is used in the calculation of the line box height [â¦] After the definition of 'vertical-align': The following values only have meaning with respect to a parent inline[DEL: -level :DEL] element, or to the strut of a parent [DEL: block-level, table-cell, table-caption or inline-block :DEL] [INS: block container :INS] element. C.7.59 Section 10.8.1 Leading and half-leading [2010-07-19] Clarify text: On a block-level, table-cell, table-caption or inline-block element whose content is composed of inline-level elements, 'line-height' specifies the minimal height of line boxes within the element. The minimum height consists of a minimum height above the [DEL: block's :DEL] baseline and a minimum depth below it, exactly as if each line box starts with a zero-width inline box with the [DEL: block's :DEL] [INS: element's :INS] font and line height properties. [DEL: (what TEX calls a "strut"). :DEL] [INS: We call that imaginary box a "strut." (The name is inspired by TeX.). :INS] C.7.60 Section 10.8.1 Leading and half-leading [2010-08-20] Remove text that talks about the âcontent areaâ of an inline box and about âcenter verticallyâ and instead make it more explicit how leading is added to a glyph: leading is added above and below a hypothetical box around each glyph that represents the (normal or ideal) height of a line of text in that font, as given in the font metrics. Add a note referring to 10.6.1 (which defines that the content area is undefined) and explaining that the exact position of backgrounds and borders relative to the line box is undefined. Also add a note about how to find the relevant metrics in OpenType and TrueType fonts. C.7.61 Section 10.8.1 Leading and half-leading [2010-08-20] Clarify some imprecise terms: When an element contains text that is rendered in more than one font, user agents may determine the [INS: 'normal' :INS] 'line-height' value according to the largest font size. Generally, when there is only one value of 'line-height' for all inline boxes in a [DEL: paragraph :DEL] [INS: block container box :INS] (and no [DEL: tall images :DEL] [INS: replaced elements, inline-block elements, etc. :INS] ), the above will ensure that baselines of successive lines are exactly 'line-height' apart. This is important when columns of text in different fonts have to be aligned, for example in a table. C.7.62 Section 11.1 Overflow and clipping [2010-10-25] Clarify which ancestors are meant: * A descendant box is positioned absolutely, partly outside the box. Such boxes are not always clipped by the overflow property on their ancestors; [INS: specifically, they are not clipped by the overflow of any ancestor between themselves and their containing block :INS] C.7.63 Section 11.1.1 Overflow: the 'overflow' property [2010-08-06] The phrase âcontaining blockâ in the example doesn't refer to the technical term âcontaining blockâ but simply to the containing box. Change âcontaining [DEL: block :DEL] â to âcontaining [INS: div :INS] .â C.7.64 Section 11.1.1 Overflow: the 'overflow' property [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â This property specifies whether content of a [DEL: block-level :DEL] [INS: block container :INS] element is clipped when it overflows the element's box. C.7.65 Section 11.1.1 Overflow: the 'overflow' property [2010-10-25] Add missing inline-table: Applies to: non-replaced block-level elements, table cells, [INS: inline-table, :INS] and inline-block elements C.7.66 Section 11.1.2 Clipping: the 'clip' property [2010-10-25] The computed value of 'auto' is 'auto' also when 'auto' is specified inside 'rect()': Computed value: [DEL: For rectangle values, a rectangle consisting of four computed lengths; otherwise, as specified :DEL] [INS: 'auto' if specified as 'auto', otherwise a rectangle with four values, each of which is 'auto' if specified as 'auto' and the computed length otherwise :INS] And: , , , and may either have a value or 'auto'. Negative lengths are permitted. The value 'auto' means that a given edge of the clipping region will be the same as the edge of the element's generated border box (i.e., 'auto' means the same as '0' for and (in left-to-right text, in right-to-left text), the same as the [DEL: computed :DEL] [INS: used :INS] value of the height plus the sum of vertical padding and border widths for , and the same as the [DEL: computed :DEL] [INS: used :INS] value of the width plus the sum of the horizontal padding and border widths for (in left-to-right text, in right-to-left text), such that four 'auto' values result in the clipping region being the same as the element's border box). C.7.67 Section 12.5 Lists [2010-10-05] Improve wording: the marker box of a list item isn't âoptional,â it is sometimes absent. Change: CSS 2.1 offers basic visual formatting of lists. An element with 'display: list-item' generates a principal box for the element's content [DEL: and an optional marker box :DEL] [INS: and, depending on the values of 'list-style-type' and 'list-style-image', possibly also a marker box :INS] as a visual indication that the element is a list item. C.7.68 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2010-07-14] Because of persistent incompatibilites between implementations, the constraints on the position of 'outside' markers are relaxed in the presence of floats. This will be fixed in a future specification. C.7.69 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2010-08-06] The 'armenian' list-style-type refers to uppercase Armenian numbering. C.7.70 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2010-08-06] Define the order of 'inside' marker boxes and ':before' pseudo-elements: inside The marker box is [INS: placed as :INS] the first inline box in the principal block box, [DEL: after which the element's content flows :DEL] [INS: before the element's content and before any :before pseudo-elements :INS] . C.7.71 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2010-08-06] CSS 2.1 does not specify the precise location of an 'outside' marker box, including its z-order. Append: CSS 2.1 does not specify the precise location of the marker box [INS: or its position in the painting order :INS] C.7.72 Section 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties [2010-11-25] Because of historical ambiguity, CSS level 2 does not yet require the marker to be visible when 'list-style-position' is 'outside' and 'overflow' is other than 'visible'. Insert in the definition of 'outside': [INS: In CSS 2.1, a UA may hide the marker if the element's 'overflow' is other than 'visible'. (This is expected to change in the future.) :INS] C.7.73 Section 13.2 Page boxes: the @page rule [2010-07-07] The @page rule can contain not just declarations but also other @-rules. (There aren't any such nested @-rules defined in level 2, but there are in level 3.) An @page rule consists of the keyword "@page", followed by an optional page selector, followed by a block [DEL: of declarations :DEL] [INS: containing declarations and at-rules :INS] . [INS: Note: CSS level 2 has no at-rules that may appear inside @page, but such at-rules are expected to be defined in level 3. :INS] And add just above section 13.2.1: [INS: The rules for handling malformed declarations, malformed statements, and invalid at-rules inside @page are as defined in section 4.2, with the following addition: when the UA expects the start of a declaration or at-rule (i.e., an IDENT token or an ATKEYWORD token) but finds an unexpected token instead, that token is considered to be the first token of a malformed declaration. I.e., the rule for malformed declarations, rather than malformed statements is used to determine which tokens to ignore in that case. :INS] C.7.74 Section 13.2.2 Page selectors: selecting left, right, and first pages [2010-10-25] Whether the first page of a document is :left or :right depends on the major writing direction. Give an example of how: All pages are automatically classified by user agents into either the :left or :right pseudo-class. [INS: Whether the first page of a document is :left or :right depends on the major writing direction of the root element. For example, the first page of a document with a left-to-right major writing direction would be a :right page, and the first page of a document with a right-to-left major writing direction would be a :left page. To explicitly force a document to begin printing on a left or right page, authors can insert a page break before the first generated box. :INS] And in 13.3.1: [DEL: Whether the first page of a document is :left or :right depends on the major writing direction of the document. :DEL] C.7.75 Section 13.3.2 Breaks inside elements: 'orphans', 'widows' [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â Change for both 'orphans' and 'widows': Applies to: [DEL: block-level :DEL] [INS: block container :INS] elements And change: The 'orphans' property specifies the minimum number of lines in a block [DEL: element :DEL] [INS: container :INS] that must be left at the bottom of a page. The 'widows' property specifies the minimum number of lines in a block [DEL: element :DEL] [INS: container :INS] that must be left at the top of a page. Examples of how they are used to control page breaks are given below. C.7.76 Section 13.3.3 Allowed page breaks [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â Change: 1. In the vertical margin between block[INS: -level :INS] boxes. [â¦] 2. Between line boxes inside a block [INS: container :INS] box. 3. Between the content edge of a block [INS: container :INS] box and the outer edges of its child content [â¦] C.7.77 Section 15.3 Font family: the 'font-family' property [2010-07-19] The specification was ambiguous as to whether parentheses, brackets and braces in font names must always be escaped, or only when needed to conform to the syntax for declarations. Because of that, and because of the many bugs in implementations, all font names must now either be quoted, or be escaped so as to consist of only identifiers. C.7.78 Section 15.3.1 Generic font families [2010-08-26] Make it clearer that CSS does not try to define what fonts are serif or sans-serif: 15.3.1.1 serif Glyphs of serif fonts, as the term is used in CSS, [INS: tend to :INS] have finishing strokes, flared or tapering ends, or have actual serifed endings (including slab serifs). [â¦] 15.3.1.2 sans-serif Glyphs in sans-serif fonts, as the term is used in CSS, [INS: tend to :INS] have stroke endings that are plain â [DEL: without any :DEL] [INS: with little or no :INS] flaring, cross stroke, or other ornamentation. [â¦] C.7.79 Section 15.6 Font boldness: the 'font-weight' property [2010-04-19] The meaning of the keywords 'bolder' and 'lighter' no longer depends on both the inherited weight and the actually used font, but only on the inherited weight. C.7.80 Section 15.6 Font boldness: the 'font-weight' property [2010-10-13] Clarify the algorithm for mapping CSS font weight values to the actual weights of a font and make it normative: The association of other weights within a family to the numerical weight values is intended only to preserve the ordering of darkness within that family. However, the following heuristics tell how the assignment is done in typical cases: * If the font family already uses a numerical scale with nine values (like e.g., OpenType does), the font weights should be mapped directly. * If there is both a face labeled Medium and one labeled Book, Regular, Roman or Normal, then the Medium is normally assigned to the '500'. * The font labeled "Bold" will often correspond to the weight value '700'. [INS: Once the font family's weights are mapped onto the CSS scale, missing weights are selected as follows: :INS] * [DEL: If there are fewer then 9 weights in the family, the default algorithm for filling the "holes" is as follows. If '500' is unassigned, it will be assigned the same font as '400'. If any of the values '600', '700', '800' or '900' remains unassigned, they are assigned to the same face as the next darker assigned keyword, if any, or the next lighter one otherwise. If any of '300', '200' or '100' remains unassigned, it is assigned to the next lighter assigned keyword, if any, or the next darker otherwise. :DEL] * [INS: If the desired weight is less than 400, weights below the desired weight are checked in descending order followed by weights above the desired weight in ascending order until a match is found. :INS] * [INS: If the desired weight is greater than 500, weights above desired weight are checked in ascending order followed by weights below the desired weight in descending order until a match is found. :INS] * [INS: If the desired weight is 400, 500 is checked first and then the rule for desired weights less than 400 is used. :INS] * [INS: If the desired weight is 500, 400 is checked first and then the rule for desired weights less than 400 is used. :INS] C.7.81 Section 15.7 Font size: the 'font-size' property [2010-08-06] Changed âPercentages: refer to [DEL: parent element's :DEL] font sizeâ to âPercentages: refer to [INS: inherited :INS] font sizeâ so that it uses the same terminology as Section 4.3.3. C.7.82 Section 16.1 Indentation: the 'text-indent' property [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â Change: Applies to: [DEL: block-level elements, table cells and inline blocks :DEL] [INS: block containers :INS] [â¦] This property specifies the indentation of the first line of text in a block [INS: container :INS] . C.7.83 Section 16.1 Indentation: the 'text-indent' property [2010-10-25] Clarify that the âfirst lineâ of the âfirst box,â etc., is the same as the âfirst formatted lineâ of chapter 5: [INS: 'Text-indent' only affects a line if it is the first formatted line of an element. For example, the first line of an anonymous block box is only affected if it is the first child of its parent element. :INS] C.7.84 Section 16.2 Alignment: the 'text-align' property [2010-07-19] The value 'pre-line' of 'white-space' does not inhibit justification. (Only lines that end with an explicit newline aren't justified, as is the case for any value of 'white-space'.) But, 'pre-wrap' does inhibit justification. Replace [DEL: If the computed value of text-align is 'justify' while the computed value of white-space is 'pre' or 'pre-line', the actual value of text-align is set to the initial value. :DEL] with [INS: If an element has a computed value for 'white-space' of 'pre' or 'pre-wrap', then neither the glyphs of that element's text content nor its white space may be altered for the purpose of justification. :INS] C.7.85 Section 16.2 Alignment: the 'text-align' property [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â Change: Applies to: [DEL: block-level elements, table cells and inline blocks :DEL] [INS: block containers :INS] This property describes how inline[INS: -level :INS] content of a block [INS: container :INS] is aligned. And: [â¦] In the case of 'left', 'right' and 'center', this property specifies how the inline[INS: -level :INS] boxes within each line box align with respect to the line box's left and right sides; alignment is not with respect to the viewport. In the case of 'justify', this property specifies that the inline[INS: -level :INS] boxes are to be made flush with both sides of the block [INS: container :INS] if possible, by expanding or contracting the contents of inline boxes, else aligned as for the initial value. C.7.86 Section 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property [2010-08-24] Clarify that 'text-decoration' does not propagate to inline-table and inline-block elements. Change: This property describes decorations that are added to the text of an element using the element's color. When specified on [DEL: an inline element, it affects all the boxes generated by that element; for all other elements, the decorations are propagated to an anonymous inline box that wraps all the in-flow inline children of the element, and to any block-level in-flow descendants. It is not, however, further propagated to floating and absolutely positioned descendants, nor to the contents of 'inline-table' and 'inline-block' descendants. :DEL] [INS: or propagated to an inline element, it affects all the boxes generated by that element, and is further propagated to any in-flow block-level boxes that split the inline (see section 9.2.1.1). For block containers that establish an inline formatting context, the decorations are propagated to an anonymous inline element that wraps all the in-flow inline-level children of the block container. For all other elements it is propagated to any in-flow children. Note that text decorations are not propagated to floating and absolutely positioned descendants, nor to the contents of atomic inline-level descendants such as inline blocks and inline tables. :INS] and: [DEL: If an element contains no text, user agents must refrain from rendering these text decorations on the element. For example, images will not be underlined. :DEL] [INS: User agents must not render these text decorations on content that is not text. For example, images and inline blocks must not be underlined. :INS] C.7.87 Section 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property [2010-10-05] CSS 2.1 does not specify if a text decoration that is specified on a transparent element ('visibility: hidden') is itself transparent, or only transparent where the text is transparent. Add this note: [INS: Note. If an element E has both 'visibility: hidden' and 'text-decoration: underline', the underline is invisible (although any decoration of E's parent is visible.) However, CSS 2.1 does not specify if the underline is visible or invisible in E's children: :INS] [INS: underlined or not? :INS] [INS: This is expected to be specified in level 3 of CSS. :INS] C.7.88 Section 16.4 Letter and word spacing: the 'letter-spacing' and 'word-spacing' properties [2010-04-19] Word spacing does not affect fixed-width spaces. Change: Word spacing affects each space (U+0020)[DEL: , :DEL] [INS: and :INS] non-breaking space (U+00A0) [DEL: and ideographic space (U+3000) :DEL] , left in the text after the white space processing rules have been applied. [INS: The effect of the property on other word-separator characters is undefined. However general punctuation, characters with zero advance width (such as the zero with space U+200B) and fixed-width spaces (such as U+3000 and U+2000 through U+200A) are not affected. :INS] C.7.89 Section 16.6 White space: the 'white-space' property [2010-10-25] If the document language specifies how newlines are represented, those newlines must be passed to the CSS UA as line feed (LF) characters. If the document language does not define how newlines are expressed (e.g., if text is inserted with the 'content' property), the CSS UA must treat CR, and CRLF as if they were LF: Newlines in the source can be represented by a carriage return (U+000D), a linefeed (U+000A) or both (U+000D U+000A) or by some other mechanism that identifies the beginning and end of document segments, such as the SGML RECORD-START and RECORD-END tokens. The CSS 'white-space' processing model assumes all newlines have been normalized to line feeds. [INS: UAs that recognize other newline representations must apply the white space processing rules as if this normalization has taken place. If no newline rules are specified for the document language, each carriage return (U+000D) and CRLF sequence (U+000D U+000A) in the document text is treated as single line feed character. This default normalization rule also applies to generated content. :INS] [â¦] 1. Each tab (U+0009), [DEL: carriage return (U+000D), :DEL] or space (U+0020) character surrounding a linefeed (U+000A) character is removed if 'white-space' is set to 'normal', 'nowrap', or 'pre-line'. C.7.90 Section 16.6.1 The 'white-space' processing model [2010-08-06] The sentence that absolutely positioned elements do not create line breaking opportunities is normative, not informative. C.7.91 Section 16.6.1 The 'white-space' processing model [2010-08-06] The first paragraph is moved to 9.2.2.1. Also, as is clear from the latter section, the âshouldâ is a âmustâ: Any text that is directly contained inside a block [INS: container :INS] element (not inside an inline element) [DEL: should :DEL] [INS: must :INS] be treated as an anonymous inline element. C.7.92 Section 16.6.1 The 'white-space' processing model [2010-08-24] More consistent use of âinline-levelâ and âblock-level.â Change: Then, the [DEL: entire block is rendered :DEL] [INS: block container's inlines are laid out :INS] . C.7.93 Section 17.2 The CSS table model [2010-08-04] Clarify that the term ârow groupâ includes header groups and footer groups as well: Thus, the table model consists of tables, captions, rows, row groups [INS: (including header groups and footer groups) :INS] , columns, column groups, and cells. C.7.94 Section 17.2.1 Anonymous table objects [2010-08-24] XML and HTML5, unlike SGML, do not automatically remove insignificant white space. Change the rules for generating anonymous table elements to suppress most white space between elements, rather than consider it the content of an anonymous table cell. C.7.95 Section 17.2.1 Anonymous table objects [2010-08-24] The static position of absolutely positioned elements between table cells or rows was not very useful. Define that the static position of such an element is found not just as if the element had 'position: static', but also had 'display: inline' and zero width and height. C.7.96 Section 17.4 Tables in the visual formatting model [2010-04-19] The caption of the image still describes the image as it was in the previous version. Change: Diagram of a table with a caption above it[DEL: ; the top margin of the caption is collapsed with the top margin of the table :DEL] . C.7.97 Section 17.4 Tables in the visual formatting model [2010-10-13] Clarify which of the two boxes generated by a table element is the principal box: In both cases, the table [DEL: box :DEL] generates [DEL: an anonymous box :DEL] [INS: a principal block box called the table wrapper box :INS] that contains the table box itself and any caption boxes (in document order). [INS: The table box is a block-level box that contains the table's internal table boxes. :INS] The caption boxes are block-level boxes that retain their own content, padding, margin, and border areas, and are rendered as normal [DEL: blocks :DEL] [INS: block boxes :INS] inside the [DEL: anonymous :DEL] [INS: table wrapper :INS] box. Whether the caption boxes are placed before or after the table box is decided by the 'caption-side' property, as described below. The [DEL: anonymous :DEL] [INS: table wrapper :INS] box is a 'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level. The [DEL: anonymous :DEL] [INS: table wrapper :INS] box establishes a block formatting context. The table box (not the [DEL: anonymous :DEL] [INS: table wrapper :INS] box) is used when doing baseline vertical alignment for an 'inline-table'. The width of the [DEL: anonymous :DEL] [INS: table wrapper :INS] box is the border-edge width of the table box inside it, as described by section 17.5.2. Percentages on 'width' and 'height' on the table are relative to the [DEL: anonymous :DEL] [INS: table wrapper :INS] box's containing block, not the [DEL: anonymous :DEL] [INS: table wrapper :INS] box itself. The computed values of properties 'position', 'float', 'margin-*', 'top', 'right', 'bottom', and 'left' on the table box are used on the [DEL: anonymous :DEL] [INS: table wrapper :INS] box instead of the table box. The table box uses the initial values for those properties. C.7.98 Section 17.5.2.2 Automatic table layout [2010-10-25] The width of the table caption contributes to the width of the table if 'table-layout' is 'auto': This gives a maximum and minimum width for each column. [INS: The caption width minimum (CAPMIN) is determined by calculating for each caption the minimum caption outer width as the MCW of a hypothetical table cell that contains the caption formatted as "display: block". The greatest of the minimum caption outer widths is CAPMIN. :INS] Column [INS: and caption :INS] widths influence the final table width as follows: 1. If the 'table' or 'inline-table' element's 'width' property has a computed value (W) other than 'auto', the [DEL: property's value as used for layout :DEL] [INS: used width :INS] is the greater of W[INS: , CAPMIN, :INS] and the minimum width required by all the columns plus cell spacing or borders (MIN). If [DEL: W :DEL] [INS: the used width :INS] is greater than MIN, the extra width should be distributed over the columns. 2. If the 'table' or 'inline-table' element has 'width: auto', the [DEL: table width used for layout :DEL] [INS: used width :INS] is the greater of the table's containing block width[INS: , CAPMIN, :INS] and MIN. However, if [INS: either CAPMIN or :INS] the maximum width required by the columns plus cell spacing or borders (MAX) is less than that of the containing block, use [DEL: MAX :DEL] [INS: max(MAX, CAPMIN) :INS] . C.7.99 Section 17.5.3 Table height algorithms [2010-07-15] Clarify that the height of a table row can be influenced by 'vertical-align' and 'height', but the content box of the table cell is not affected. [â¦] it is the maximum of the row's specified 'height', [INS: the specified 'height' of each cell in the row, :INS] and the minimum height (MIN) required by the cells and In CSS 2.1, the height of a cell box is the [DEL: maximum of the table cell's 'height' property and the minimum height required by the content (MIN). :DEL] [INS: minimum height required by the content. The table cell's 'height' property can influence the height of the row, but it does not increase the height of the cell box. :INS] [DEL: A value of 'auto' for 'height' implies that the value MIN will be used for layout. :DEL] C.7.100 Section 17.5.4 Horizontal alignment in a column [2010-08-24] More consistent use of âinline-level.â Change: The horizontal alignment of [DEL: a cell's inline content :DEL] [INS: inline-level content :INS] within a cell box C.7.101 Section B.2 Informative references [2010-08-06] BCP 47 replaces RFC 3066. C.7.102 Section D. Default style sheet for HTML 4 [2010-10-05] HTML defines that HTML's block elements represent a Unicode embedding even if they are displayed inline by means of a style sheet. The default style sheet for HTML didn't yet express that. Add: html, address, blockquote, body, dd, div, dl, dt, fieldset, form, frame, frameset, h1, h2, h3, h4, h5, h6, noframes, ol, p, ul, center, dir, hr, menu, pre { display: block; [INS: unicode-bidi: embed :INS] } C.7.103 Section E.2 Painting order [2010-07-07] Clarification: The [DEL: stacking order for :DEL] [INS: painting order for the descendants of :INS] an element generating a stacking context (see the 'z-index' property) is: [â¦] C.7.104 Appendix G Grammar of CSS 2.1 [2010-10-25] The appendix is not normative. C.8 Changes since the working draft of 7 December 2010 C.8.1 8.3.1 Collapsing margins The section is completely rewritten to make the normative text shorter and clearer. C.8.2 10.8.1 Leading and half-leading The remark about equal line spacing is made more precise and put in green, to make it clearer that it is a note: [DEL: Generally, :DEL] [INS: Note. :INS] when there is only one value of 'line-height' for all inline boxes in a block container box [INS: and they are all in the same font :INS] (and [INS: there are :INS] no replaced elements, inline-block elements, etc.), the above will ensure that baselines of successive lines are exactly 'line-height' apart. This is important when columns of text in different fonts have to be aligned, for example in a table. C.8.3 10.3 Calculating widths and margins Added a note that the width calculation only yields a tentative value, still to be compared to 'min-width' and 'max-width' [INS: Note. The used value of 'width' calculated below is a tentative value, and may have to be calculated multiple times, depending on 'min-width' and 'max-width', see the section Minimum and maximum widths below. :INS] A similar note is added to section 10.6 about calculating heights. C.8.4 14.3 Gamma correction The section on gamma correction was removed. It existed only to help implementations on certain operating systems of the 1990s. C.8.5 11.1.2 Clipping: the 'clip' property The 2nd and 4th offsets of the clip rectangle are offsets from the left edge of the element. The 'direction' property no longer has an influence. C.8.6 9.4.2 Inline formatting contexts The words "line feed" were a typing error. The intended words are "forced line break." (The sentence was subsequently changed further as a result of another issue.) C.8.7 10.3.2 Inline, replaced elements No image formats were found that allow an intrinsic size to be expressed as a percentage. The relevant definitions are removed: [DEL: Percentage intrinsic widths are first evaluated with respect to the containing block's width, if that width does not itself depend on the replaced element's width. If it does, then the resulting layout is undefined in CSS 2.1. :DEL] Similarly in 10.6.2: [DEL: Percentage intrinsic heights are evaluated with respect to the containing block's height, if that height is specified explicitly, or if the replaced element is absolutely positioned. If neither of these conditions is met, then percentage values on such replaced elements cannot be resolved and such elements are assumed to have no intrinsic height. :DEL] And in 12.5.1: [DEL: 2. If the image's intrinsic width or height is given as a percentage, then that percentage is resolved against 1em. :DEL] C.8.8 10.1 Definition of "containing block" In CSS 2.1, it is undefined what the containing block of an absolutely positioned element is, if its nearest positioned ancestor is inline and split over multiple lines: 4. If the element has 'position: absolute' [â¦] following way; 1. In the case that the ancestor is an [DEL: inline box :DEL] [INS: inline-level element :INS] , the containing block [DEL: depends on the 'direction' property of the ancestor: :DEL] [INS: is the bounding box around the padding boxes of the first and the last inline boxes generated for that element. In CSS 2.1, if the inline element is split across multiple lines, the containing block is undefined. :INS] 1. [DEL: If the 'direction' is 'ltr', the top and left of the containing block are the top and left padding edges of the first box generated by the ancestor, and the bottom and right are the bottom and right padding edges of the last box of the ancestor. :DEL] 2. [DEL: If the 'direction' is 'rtl', the top and right are the top and right padding edges of the first box generated by the ancestor, and the bottom and left are the bottom and left padding edges of the last box of the ancestor. :DEL] [DEL: Note: This may cause the containing block's width to be negative. :DEL] C.8.9 13.2.2 Page selectors: selecting left, right, and first pages CSS 2.1 does not define if ':first' applies to the first page or the first non-blank page: [INS: If a forced break occurs before the first generated box, it is undefined in CSS 2.1 whether ':first' applies to the blank page before the break or to the page after it. :INS] C.8.10 8.3.1 Collapsing margins Added a note with a link to 9.4.2, which defines types of line boxes that exist but do not interfere with collapsing margins. * no line boxes, no clearance, no padding and no border separate them [INS: (Note that certain zero-height line boxes (see 9.4.2) are ignored for this purpose.) :INS] C.8.11 10.8 Line height calculations: the 'line-height' and 'vertical-align' properties The definition of which height is used for the different kinds of inline-level boxes is made explicit, rather than linked: 1. The height of each inline-level box in the line box is calculated. [INS: For replaced elements, inline-block elements, and inline-table elements, this is the height of their margin box; for inline boxes, this is their 'line-height'. :INS] (See "Calculating heights and margins" and the [DEL: 'line-height' property :DEL] [INS: height of inline boxes in "Leading and half-leading" :INS] .) The part of the definition that was in 10.6.2 is removed: [DEL: For 'inline' and 'inline-block' elements, the margin box is used when calculating the height of the line box. :DEL] C.8.12 10.8.1 Leading and half-leading Inserted the following before the definitions of the keywords of 'vertical-align' to define precisely which box is aligned: [INS: In the following definitions, for inline non-replaced elements, the box used for alignment is the box whose height is the 'line-height' (containing the box's glyphs and the half-leading on each side, see above). For all other elements, the box used for alignment is the margin box. :INS] Also, to make sure there always is a box whose height is 'line-height', a phrase earlier in the same section was removed: User agent must align the glyphs in a non-replaced inline box to each other by their relevant baselines[DEL: , and to nested inline boxes according to 'vertical-align' :DEL] . And another modified: The height of the inline box [DEL: is then the smallest such that it encloses all glyphs and their leading, as well as all nested inline boxes. :DEL] [INS: encloses all glyphs and their half-leading on each side and is thus exactly 'line-height'. Boxes of child elements do not influence this height. :INS] C.8.13 10.6.1 Inline, non-replaced elements Improve language: The vertical padding, border and margin of an inline, non-replaced box start at the top and bottom of the content area, [DEL: not :DEL] [INS: and has nothing to do with :INS] the 'line-height'. But only the 'line-height' is used when calculating the height of the line box. C.8.14 9.5.1 Positioning the float: the 'float' property A left float must not only not overlap a right float, but must also not be completely to the right of it. 3. The right outer edge of a left-floating box may not be to the right of the left outer edge of any right-floating box that is [DEL: to the right of :DEL] [INS: next to :INS] it. Analogous rules hold for right-floating elements. C.8.15 9.2.1.1 Anonymous block boxes An error in the description of the example: The resulting boxes would be [DEL: an anonymous block box around :DEL] [INS: a block box representing :INS] the BODY, containing an anonymous block box around C1, the SPAN block box, and another anonymous block box around C2. C.8.16 5.12.1 The :first-line pseudo-element UAs are not required to support 'vertical-align' on '::first-line'. The following properties apply to a :first-line pseudo-element: font properties, color property, background properties, 'word-spacing', 'letter-spacing', 'text-decoration', [DEL: 'vertical-align', :DEL] 'text-transform', [INS: and :INS] 'line-height'. UAs may apply other properties as well. C.8.17 16.6 White space: the 'white-space' property CSS 2.1 does not define whether the Line Separator character in Unicode and other forced line break characters (other than LF) cause a line break. (Level 3 will probably define this in detail.) pre This value prevents user agents from collapsing sequences of white space. Lines are only broken at [DEL: newlines in the source, or at occurrences of "\A" in generated content :DEL] [INS: preserved newline characters :INS] . and pre-wrap This value prevents user agents from collapsing sequences of white space. Lines are broken at [DEL: newlines in the source, at occurrences of "\A" in generated content, :DEL] [INS: preserved newline characters, :INS] and as necessary to fill line boxes. pre-line This value directs user agents to collapse sequences of white space. Lines are broken at [DEL: newlines in the source, at occurrences of "\A" in generated content, :DEL] [INS: preserved newline characters, :INS] and as necessary to fill line boxes. and add this paragraph: [INS: UAs must recognize line feeds (U+000A) as newline characters. UAs may additionally treat other forced break characters as newline characters per UAX14. :INS] C.8.18 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties CSS 2.1 omits to define how the implicit counters of 'list-item' are reset and incremented. This will be specified in level 3. [INS: CSS 2.1 does not define how the list numbering is reset and incremented. This is expected to be defined in the CSS List Module [CSS3LIST]. :INS] C.8.19 9.7 Relationships between 'display', 'position', and 'float' Some UAs treat 'display: list-item' on the root element as 'block'. Allow that behavior for now: 4. Otherwise, if the element is the root element, 'display' is set according to the table below[INS: , except that it is undefined in CSS 2.1 whether a specified value of 'list-item' becomes a computed value of 'block' or 'list-item' :INS] . C.8.20 9.4.2 Inline formatting contexts Empty line boxes aren't generated at all, rather than just ignored for margin collapsing. But their virtual position must still be calculated if they contain empty inlines with absolutely positioned or floating descendants: [INS: Line boxes are created as needed to hold inline-level content within an inline formatting context. :INS] Line boxes that contain no text, no preserved white space, no inline elements with non-zero margins, padding, or borders, and no other in-flow content (such as images, inline blocks or inline tables), and do not end with a [DEL: line feed :DEL] [INS: preserved newline :INS] must be treated as zero-height line boxes [INS: for the purposes of determining the positions of any elements inside of them, and treated as not existing for any other purpose. :INS] [DEL: For the purposes of margin collapsing, this line box must be ignored. :DEL] C.8.21 4.1.9 Comments Use same phrasing for comment tokens as in section 4.1.1: They may occur anywhere [DEL: between :DEL] [INS: outside other :INS] tokens C.8.22 12.5.1 Lists: the 'list-style-type', 'list-style-image', 'list-style-position', and 'list-style' properties The size computation of list marker images without an intrinsic size is modified to be consistent with how image sizes are computed in other places, using 1em for the available width and 1:1 for the default aspect ratio: 1. [DEL: If the image has an intrinsic width or height, then that intrinsic width/height becomes the image's used width/height. :DEL] [INS: If the image has a intrinsic width and height, the used width and height are the intrinsic width and height. :INS] 2. [DEL: If the image has no intrinsic ratio and a ratio cannot be calculated from its width and height, then its intrinsic ratio is assumed to be 1:1. :DEL] [INS: Otherwise, if the image has an intrinsic ratio and either an intrinsic width or an intrinsic height, the used width/height is the same as the provided intrinsic width/height, and the used value of the missing dimension is calculated from the provided dimension and the ratio. :INS] 3. [DEL: If the image has a width but no height, its height is calculated from the intrinsic ratio. :DEL] [INS: Otherwise, if the image has an intrinsic ratio, the used width is 1em and the used height is calculated from this width and the intrinsic ratio. If this would produce a height larger than 1em, then the used height is instead set to 1em and the used width is calculated from this height and the intrinsic ratio. :INS] 4. [DEL: If the image's height cannot be resolved from the rules above, then the image's height is assumed to be 1em. :DEL] [INS: Otherwise, the image's used width is its intrinsic width if it has one, or else 1em. The image's used height is its intrinsic height if it has one, or else 1em. :INS] 5. [DEL: If the image has no intrinsic width, then its width is calculated from the resolved height and the intrinsic ratio. :DEL] C.8.23 9.5.1 Positioning the float: the 'float' property Because of lack of sufficient implementations, the top of a floating box is allowed to be above the top of earlier boxes in certain difficult cases. Add after the numbered list: [INS: But in CSS 2.1, if, within the block formatting context, there is an in-flow negative vertical margin such that the float's position is above the position it would be at were all such negative margins set to zero, the position of the float is undefined. :INS] C.8.24 9.3 Positioning schemes Add formal definitions of the terms âout of flow,â âin-flowâ and âflow of an elementâ: [INS: An element is called out of flow if it is floated, absolutely positioned, or is the root element. An element is called in-flow if it is not out-of-flow. The flow of an element A is the set consisting of A and all in-flow elements whose nearest out-of-flow ancestor is A. :INS] C.8.25 9.10 Text direction: the 'direction' and 'unicode-bidi' properties The list of features affected by 'direction' is not meant to be exclusive: This property specifies the base writing direction of blocks and the direction of embeddings and overrides (see 'unicode-bidi') for the Unicode bidirectional algorithm. In addition, it specifies [INS: such things as :INS] the direction of table column layout, the direction of horizontal overflow, the position of an incomplete last line in a block in case of 'text-align: justify'. C.8.26 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property Whether the effect of 'text-decoration' propagates into tables may be the subject of a separate property in level 3: [â¦] When specified on or propagated to an inline element, it affects all the boxes generated by that element, and is further propagated to any in-flow block-level boxes that split the inline (see section 9.2.1.1). [INS: But, in CSS 2.1, it is undefined whether the decoration propagates into block-level tables. :INS] C.8.27 16.3.1 Underlining, overlining, striking, and blinking: the 'text-decoration' property Clarify that the text for 'inset' and 'outset' only talks about how the border styles look (and not, e.g., about which style takes priority): *inset In the separated borders model, the border makes the entire box look as though it were embedded in the canvas. In the collapsing border model, [INS: drawn the :INS] same as 'ridge'. *outset In the separated borders model, the border makes the entire box look as though it were coming out of the canvas. In the collapsing border model, [INS: drawn the :INS] same as 'groove'. C.8.28 10.4 Minimum and maximum widths: 'min-width' and 'max-width' Added: [INS: In CSS 2.1, the effect of 'min-width' and 'max-width' on tables, inline tables, table cells, table columns, and column groups is undefined. :INS] C.8.29 9.3.2 Box offsets: 'top', 'right', 'bottom', 'left' 'Top', right', 'bottom' and 'left' are always computed, independent of the value of other properties: 'top' Value: | | auto | inherit Initial: auto Applies to: positioned elements Inherited: no Percentages: refer to height of containing block Media: visual Computed value: [DEL: for 'position:static', 'auto'. Otherwise: :DEL] if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, 'auto'. Analogously for 'right', 'bottom' and 'left'. C.8.30 9.2.1.1 Anonymous block boxes Clarify that the two parts of an inline that is split by a block are on opposite sides of the block: When an inline box contains an in-flow block-level box, the inline box (and its inline ancestors within the same line box) are broken around the block-level box (and any block-level siblings that are consecutive or separated only by collapsible whitespace and/or out-of-flow elements), [DEL: dividing :DEL] [INS: splitting :INS] the inline box into two pieces (even if either side is empty)[INS: , one on each side of the block-level box(es) :INS] . C.8.31 17.4 Tables in the visual formatting model More precise rule for which properties apply to the table box and which to the table wrapper box: The computed values of properties 'position', 'float', 'margin-*', 'top', 'right', 'bottom', and 'left' on the table [DEL: box :DEL] [INS: element :INS] are used on the table wrapper box [DEL: instead of :DEL] [INS: and not :INS] the table box[DEL: . The table box uses the initial values for those properties. :DEL] [INS: ; all other values of non-inheritable properties are used on the table box and not the table wrapper box. (Where the table element's values are not used on the table and table wrapper boxes, the initial values are used instead.) :INS] C.8.32 11.1.2 Clipping: the 'clip' property Some text and arrows were added to the example to make it easier to see where the four offsets of the clip rectangle are applied: Two clipping regions [D] C.8.33 13.2 Page boxes: the @page rule The definition of the @page rule didn't mention explicitly (except with examples) that white space is allowed: An @page rule consists of the keyword "@page", followed by an optional page selector, followed by a block containing declarations and at-rules. [INS: Comments and white space are allowed, but optional, between the @page token and the page selector and between the page selector and the block. :INS] C.8.34 4.1.1 Tokenization Added an example to illustrate what is meant by âthe longest matchâ in the tokenizer: Example(s): [INS: For example, the rule of the longest match means that "red-->" is tokenized as the IDENT "red--" followed by the DELIM ">", rather than as an IDENT followed by a CDC. :INS] C.8.35 4.2 Rules for handling parsing errors Clarify that âend of lineâ means an end of line character, i.e., the end of file is not an end of line: User agents must close strings upon reaching the end of a line [INS: (i.e., before an unescaped line feed, carriage return or form feed character) :INS] , but then drop the construct (declaration or rule) in which the string was found. C.8.36 3.1 Definitions There may soon be a newer version of HTML then HTML4: An HTML user agent is one that supports [INS: one or more of :INS] the HTML [DEL: 2.x, HTML 3.x, or HTML 4.x :DEL] specifications. A user agent that supports XHTML [XHTML], but not HTML [DEL: (as listed in the previous sentence) :DEL] is not considered an HTML user agent for the purpose of conformance with this specification. C.8.37 4.3.4 URLs and URIs Make the note about parsing URLs shorter and clearer: Note that COMMENT tokens cannot occur within other tokens: thus, "url(/*x*/pic.png)" denotes the URI "/*x*/pic.png", not "pic.png". C.8.38 9.5 Floats Clarify the note: Note: this means that floats with zero [INS: outer :INS] height or negative [INS: outer :INS] height do not shorten line boxes. C.8.39 11.1.1 Overflow: the 'overflow' property Shorten the âapplies toâ line: 'overflow' Value: visible | hidden | scroll | auto | inherit Initial: visible Applies to: [DEL: non-replaced block-level elements, table cells, inline-table, and inline-block elements :DEL] [INS: block containers :INS] Inherited: no Percentages: N/A Media: visual Computed value: as specified C.8.40 9.2.1.1 Anonymous block boxes Clarify how block-level elements inside inline elements are affected by relative positioning: When such an inline box is affected by relative positioning, [DEL: the relative positioning :DEL] [INS: any resulting translation :INS] also affects the block-level box contained in the inline box. C.8.41 16.2 Alignment: the 'text-align' property Text is justified within the line box, which may be narrower than the block box: In the case of 'justify', this property specifies that the inline-level boxes are to be made flush with both sides of the [DEL: block container :DEL] [INS: line box :INS] if possible, [â¦] C.8.42 9.5 Floats Only the current and later line boxes can be shortened by a float. Earlier line boxes, if the float ends up next to them, will overlap the float instead: Since a float is not in the flow, non-positioned block boxes created before and after the float box flow vertically as if the float did not exist. However, [INS: the current and subsequent :INS] line boxes created next to the float are shortened to make room for the margin box of the float. C.8.43 9.4.2 Inline formatting contexts A float may cause a gap between line boxes: [â¦] Thus, a paragraph is a vertical stack of line boxes. Line boxes are stacked with no vertical separation [INS: (except as specified elsewhere) :INS] and they never overlap. C.8.44 5.12 Pseudo-elements Added a note to make it explicit that CSS 2.1 does not define ':first-line' and ':first-letter' completely: [INS: Note that the sections below do not define the exact rendering of ':first-line' and ':first-letter' in all cases. A future level of CSS may define them more precisely. :INS] C.8.45 9.5 Floats Clarify that âoverlap a floatâ means overlap the margin box of the float: The border box of a table, a block-level replaced element, or an element in the normal flow that establishes a new block formatting context (such as an element with 'overflow' other than 'visible') must not overlap [INS: the margin box of :INS] any floats in the same block formatting context as the element itself. C.8.46 9.5 Floats A line box next to a float is not shortened if it already doesn't overlap the float: [â¦] However, the current and subsequent line boxes created next to the float are shortened [INS: as necessary :INS] to make room for the margin box of the float. C.8.47 14.2.1 Background properties: 'background-color', 'background-image', 'background-repeat', 'background-attachment', 'background-position', and 'background' Because of insufficient implementations of background images with an intrinsic ratio but no intrinsic size, add this note: [INS: However, the position is undefined in CSS 2.1 if the image has an intrinsic ratio, but no intrinsic size. :INS] C.8.48 9.2.4 The 'display' property Because some aspects of 'run-in' (most notably if and how 'clear' should apply to run-in elements when they are inline) are still under discussion, 'run-in' has been reclassified as a level 3 feature. Change in section 9.2.4: Value: inline | block | list-item | [DEL: run-in | :DEL] inline-block | table | inline-table | inline | block | list-item | run-in | inline-block | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column | table-cell | table-caption | none | inherit and [DEL: run-in :DEL] [DEL: This value creates either block or inline boxes, depending on context. Properties apply to run-in boxes based on their final status (inline-level or block-level). :DEL] Remove 'run-in' from section 9.2.1 âBlock-level elements and block boxesâ: [â¦] The following values of the 'display' property make an element block-level: 'block', 'list-item', [DEL: and 'run-in' (part of the time; see run-in boxes), :DEL] and 'table'. Remove 'run-in' from section 9.2.2 âInline-level elements and inline boxesâ: [â¦] The following values of the 'display' property make an element inline-level: 'inline', 'inline-table', [INS: and :INS] 'inline-block' [DEL: and 'run-in' (part of the time; see run-in boxes) :DEL] . [â¦] [â¦] A non-replaced element with a 'display' value of 'inline' generates an inline box. [DEL: An element with a 'display' value of 'run-in' can also generate an inline box; see run-in boxes. :DEL] Replace section 9.2.3 âRun-in boxesâ by this: 9.2.3 Run-in boxes [This section exists so that the section numbers are the same as in previous drafts. 'Display: run-in' is now defined in CSS level 3 (see CSS basic box model).] Remove 'run-in' from section 9.3 âPositioning schemesâ: 1. Normal flow. In CSS 2.1, normal flow includes block formatting of block-level boxes, inline formatting of inline-level boxes, [INS: and :INS] relative positioning of block-level and inline-level boxes[DEL: , and formatting of run-in boxes :DEL] . Remove 'run-in' from section 9.5.2 âControlling flow next to floats: the 'clear' propertyâ: [DEL: For run-in boxes, this property applies to the final block box to which the run-in box belongs. :DEL] Remove 'run-in' from section 9.7 âRelationships between 'display', 'position', and 'float'â: Specified value Computed value inline-table table inline, [DEL: run-in, :DEL] table-row-group, table-column, table-column-group, table-header-group, table-footer-group, table-row, table-cell, table-caption, inline-block block others same as specified Remove 'run-in' from section 9.10 âText direction: the 'direction' and 'unicode-bidi' propertiesâ: The final order of characters in each block container is the same as if the bidi control codes had been added as described above, markup had been stripped, and the resulting character sequence had been passed to an implementation of the Unicode bidirectional algorithm for plain text that produced the same line-breaks as the styled text. In this process, replaced elements with 'display: inline' [DEL: (and replaced elements with 'display: run-in', when they generate inline-level boxes) :DEL] are treated as neutral characters, unless their 'unicode-bidi' property has a value other than 'normal', in which case they are treated as strong characters in the 'direction' specified for the element. All other atomic inline-level boxes are treated as neutral characters always. Remove 'run-in' from section E.1 âDefinitionsâ: Tree Order Preorder depth-first traversal of the rendering tree, in logical (not visual) order for bidirectional content, after taking into account properties that move boxes around [DEL: such as the 'run-in' value of 'display' :DEL] . Remove 'run-in' from section 12.1 âThe :before and :after pseudo-elementsâ: The :before and :after pseudo-elements interact with other boxes[DEL: , such as run-in boxes, :DEL] as if they were real elements inserted just inside their associated element. and also from the subsequent example. C.8.49 6.1.2 Computed values Clarify that the keyword 'inherit' means that the specified value is the inherited value. The value is not the keyword itself. [DEL: When the specified value is not 'inherit', :DEL] the computed value of a property is determined as specified by the Computed Value line in the definition of the property. See the section on inheritance for the definition of computed values when the specified value is 'inherit'. And in 6.2.1: Each property may also have a [DEL: specified :DEL] [INS: cascaded :INS] value of 'inherit', which means that, for a given element, the property takes the same [DEL: computed :DEL] [INS: specified :INS] value as the property for the element's parent. The 'inherit' value can be used to [DEL: strengthen inherited :DEL] [INS: enforce inheritance of :INS] values, and it can also be used on properties that are not normally inherited. C.8.50 10.3.2 Inline, replaced elements Because of lack of implementations, the width of a replaced element with an intrinsic ratio but neither intrinsic with nor intrinsic height is left undefined: If 'height' and 'width' both have computed values of 'auto' and the element has an intrinsic ratio but no intrinsic height or width, [DEL: and :DEL] [INS: then the used value of 'width' is undefined in CSS 2.1. However, it is suggested that, if :INS] the containing block's width does not itself depend on the replaced element's width, then the used value of 'width' is calculated from the constraint equation used for block-level, non-replaced elements in normal flow. C.8.51 Section 9.5.2 Controlling flow next to floats: the 'clear' property Because of lack of implementations, also allow 'clear' to work in a different way for now: Computing the clearance of an element on which 'clear' is set is done by first determining the hypothetical position of the element's top border edge [DEL: within its parent block :DEL] . This position is where the actual top border edge would have been if the element had a non-zero bottom border and its 'clear' property had been 'none'. If this hypothetical position of the element's top border edge is not past the relevant floats, then clearance is introduced, and margins collapse according to the rules in 8.3.1. Then the amount of clearance is set to the greater of: 1. The amount necessary to place the border edge of the block even with the bottom outer edge of the lowest float that is to be cleared. 2. The amount necessary to place the top border edge of the block at its hypothetical position. [INS: Alternatively, clearance is set exactly to the amount necessary to place the border edge of the block even with the bottom outer edge of the lowest float that is to be cleared. :INS] [INS: Note: Both behaviors are allowed pending evaluation of their compatibility with existing Web content. A future CSS specification will require either one or the other. :INS] C.8.52 G.2 Lexical scanner The tokenizer in the appendix allowed backslashes in the URI token, in contradiction with the same token in the core grammar and the error recovery token {baduri}: [DEL: {U}{R}{L}"("{w}{string}{w}")" {return URI;} :DEL] [DEL: {U}{R}{L}"("{w}{url}{w}")" {return URI;} :DEL] [INS: "url("{w}{string}{w}")" {return URI;} :INS] [INS: "url("{w}{url}{w}")" {return URI;} :INS] C.8.53 Section 9.5.2 Controlling flow next to floats: the 'clear' property The top border edge is now well-defined in the section on collapsing margins. That is the hypothetical position to use for clearance: This position is where the actual top border edge would have been if the element [DEL: had a non-zero bottom border and its :DEL] [INS: 's :INS] 'clear' property had been 'none'. C.8.54 9.5 Floats Remove ambiguities: If a shortened line box is too small to contain any content [DEL: after the float :DEL] , then [DEL: that content :DEL] [INS: the line box :INS] is shifted downward [INS: (and its width recomputed) :INS] until either [DEL: it :DEL] [INS: some content :INS] fits or there are no more floats present. Any content in the current line before a floated box is reflowed in the [DEL: first available :DEL] [INS: same :INS] line on the other side of the float. C.8.55 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible' Removed redundancy (the top edge was already defined elsewhere) and made the implied cases for the bottom edge explicit: [DEL: If it only has inline-level children, the height is the distance between the top of the topmost line box and the bottom of the bottommost line box. :DEL] [DEL: If it has block-level children, the height is the distance between the top border-edge of the topmost block-level child box that does not have margins collapsed through it and the bottom border-edge of the bottommost block-level child box that does not have margins collapsed through it. However, if the element has a non-zero top padding and/or top border, or is the root element, then the content starts at the top margin edge of the topmost child. (The first case expresses the fact that the top and bottom margins of the element collapse with those of the topmost and bottommost children, while in the second case the presence of the padding/border prevents the top margins from collapsing.) Similarly, if the bottom margin of the block does not collapse with the bottom margin of its last in-flow child, then the content ends at the bottom margin edge of the bottommost child. :DEL] [INS: The element's height is the distance from its top content edge to the first applicable of the following: :INS] 1. [INS: the bottom edge of the last line box, if the box establishes a inline formatting context with one or more lines :INS] 2. [INS: the bottom edge of the bottom (possibly collapsed) margin of its last in-flow child, if the child's bottom margin does not collapse with the element's bottom margin :INS] 3. [INS: the bottom border edge of the last in-flow child whose top margin doesn't collapse with the element's bottom margin :INS] 4. [INS: zero, otherwise :INS] Appendix D. Default style sheet for HTML 4 This appendix is informative, not normative. This style sheet describes the typical formatting of all HTML 4 ([HTML4]) elements based on extensive research into current UA practice. Developers are encouraged to use it as a default style sheet in their implementations. The full presentation of some HTML elements cannot be expressed in CSS 2.1, including replaced elements ("img", "object"), scripting elements ("script", "applet"), form control elements, and frame elements. For other elements, the legacy presentation can be described in CSS but the solution removes the element. For example, the FONT element can be replaced by attaching CSS declarations to other elements (e.g., DIV). Likewise, legacy presentation of presentational attributes (e.g., the "border" attribute on TABLE) can be described in CSS, but the markup in the source document must be changed. html, address, blockquote, body, dd, div, dl, dt, fieldset, form, frame, frameset, h1, h2, h3, h4, h5, h6, noframes, ol, p, ul, center, dir, hr, menu, pre { display: block; unicode-bidi: embed } li { display: list-item } head { display: none } table { display: table } tr { display: table-row } thead { display: table-header-group } tbody { display: table-row-group } tfoot { display: table-footer-group } col { display: table-column } colgroup { display: table-column-group } td, th { display: table-cell } caption { display: table-caption } th { font-weight: bolder; text-align: center } caption { text-align: center } body { margin: 8px } h1 { font-size: 2em; margin: .67em 0 } h2 { font-size: 1.5em; margin: .75em 0 } h3 { font-size: 1.17em; margin: .83em 0 } h4, p, blockquote, ul, fieldset, form, ol, dl, dir, menu { margin: 1.12em 0 } h5 { font-size: .83em; margin: 1.5em 0 } h6 { font-size: .75em; margin: 1.67em 0 } h1, h2, h3, h4, h5, h6, b, strong { font-weight: bolder } blockquote { margin-left: 40px; margin-right: 40px } i, cite, em, var, address { font-style: italic } pre, tt, code, kbd, samp { font-family: monospace } pre { white-space: pre } button, textarea, input, select { display: inline-block } big { font-size: 1.17em } small, sub, sup { font-size: .83em } sub { vertical-align: sub } sup { vertical-align: super } table { border-spacing: 2px; } thead, tbody, tfoot { vertical-align: middle } td, th, tr { vertical-align: inherit } s, strike, del { text-decoration: line-through } hr { border: 1px inset } ol, ul, dir, menu, dd { margin-left: 40px } ol { list-style-type: decimal } ol ul, ul ol, ul ul, ol ol { margin-top: 0; margin-bottom: 0 } u, ins { text-decoration: underline } br:before { content: "\A"; white-space: pre-line } center { text-align: center } :link, :visited { text-decoration: underline } :focus { outline: thin dotted invert } /* Begin bidirectionality settings (do not change) */ BDO[DIR="ltr"] { direction: ltr; unicode-bidi: bidi-override } BDO[DIR="rtl"] { direction: rtl; unicode-bidi: bidi-override } *[DIR="ltr"] { direction: ltr; unicode-bidi: embed } *[DIR="rtl"] { direction: rtl; unicode-bidi: embed } @media print { h1 { page-break-before: always } h1, h2, h3, h4, h5, h6 { page-break-after: avoid } ul, ol, dl { page-break-before: avoid } } Appendix E. Elaborate description of Stacking Contexts Contents * E.1 Definitions * E.2 Painting order * E.3 Notes This chapter defines the CSS 2.1 painting order in more detail than described in the rest of the specification. E.1 Definitions Tree Order Preorder depth-first traversal of the rendering tree, in logical (not visual) order for bidirectional content, after taking into account properties that move boxes around. Element In this description, "element" refers to actual elements, pseudo-elements, and anonymous boxes. Pseudo-elements and anonymous boxes are treated as descendants in the appropriate places. For example, an outside list marker comes before an adjoining ':before' box in the line box, which comes before the content of the box, and so forth. E.2 Painting order The bottom of the stack is the furthest from the user, the top of the stack is the nearest to the user: | | | | | | | | ⦠⻠| | | user z-index: canvas -1 0 1 2 The stacking context background and most negative positioned stacking contexts are at the bottom of the stack, while the most positive positioned stacking contexts are at the top of the stack. The canvas is transparent if contained within another, and given a UA-defined color if it is not. It is infinite in extent and contains the root element. Initially, the viewport is anchored with its top left corner at the canvas origin. The painting order for the descendants of an element generating a stacking context (see the 'z-index' property) is: 1. If the element is a root element: 1. background color of element over the entire canvas. 2. background image of element, over the entire canvas, anchored at the origin that would be used if it was painted for the root element. 2. If the element is a block, list-item, or other block equivalent: 1. background color of element unless it is the root element. 2. background image of element unless it is the root element. 3. border of element. Otherwise, if the element is a block level table: 1. table backgrounds (color then image) unless it is the root element. 2. column group backgrounds (color then image). 3. column backgrounds (color then image). 4. row group backgrounds (color then image). 5. row backgrounds (color then image). 6. cell backgrounds (color then image). 7. all table borders (in tree order for separated borders). 3. Stacking contexts formed by positioned descendants with negative z-indices (excluding 0) in z-index order (most negative first) then tree order. 4. For all its in-flow, non-positioned, block-level descendants in tree order: If the element is a block, list-item, or other block equivalent: 1. background color of element. 2. background image of element. 3. border of element. Otherwise, the element is a table: 1. table backgrounds (color then image). 2. column group backgrounds (color then image). 3. column backgrounds (color then image). 4. row group backgrounds (color then image). 5. row backgrounds (color then image). 6. cell backgrounds (color then image). 7. all table borders (in tree order for separated borders). 5. All non-positioned floating descendants, in tree order. For each one of these, treat the element as if it created a new stacking context, but any positioned descendants and descendants which actually create a new stacking context should be considered part of the parent stacking context, not this new one. 6. If the element is an inline element that generates a stacking context, then: 1. For each line box that the element is in: 1. Jump to 7.2.1 for the box(es) of the element in that line box (in tree order). 7. Otherwise: first for the element, then for all its in-flow, non-positioned, block-level descendants in tree order: 1. If the element is a block-level replaced element, then: the replaced content, atomically. 2. Otherwise, for each line box of that element: 1. For each box that is a child of that element, in that line box, in tree order: 1. background color of element. 2. background image of element. 3. border of element. 4. For inline elements: 1. For all the element's in-flow, non-positioned, inline-level children that are in this line box, and all runs of text inside the element that is on this line box, in tree order: 1. If this is a run of text, then: 1. any underlining affecting the text of the element, in tree order of the elements applying the underlining (such that the deepest element's underlining, if any, is painted topmost and the root element's underlining, if any, is drawn bottommost). 2. any overlining affecting the text of the element, in tree order of the elements applying the overlining (such that the deepest element's overlining, if any, is painted topmost and the root element's overlining, if any, is drawn bottommost). 3. the text. 4. any line-through affecting the text of the element, in tree order of the elements applying the line-through (such that the deepest element's line-through, if any, is painted topmost and the root element's line-through, if any, is drawn bottommost). 2. Otherwise, jump to 7.2.1 for that element. For inline-block and inline-table elements: 1. For each one of these, treat the element as if it created a new stacking context, but any positioned descendants and descendants which actually create a new stacking context should be considered part of the parent stacking context, not this new one. For inline-level replaced elements: 1. the replaced content, atomically. Some of the boxes may have been generated by line splitting or the Unicode bidirectional algorithm. 2. Optionally, the outline of the element (see 10 below). 3. Optionally, if the element is block-level, the outline of the element (see 10 below). 8. All positioned descendants with 'z-index: auto' or 'z-index: 0', in tree order. For those with 'z-index: auto', treat the element as if it created a new stacking context, but any positioned descendants and descendants which actually create a new stacking context should be considered part of the parent stacking context, not this new one. For those with 'z-index: 0', treat the stacking context generated atomically. 9. Stacking contexts formed by positioned descendants with z-indices greater than or equal to 1 in z-index order (smallest first) then tree order. 10. Finally, implementations that do not draw outlines in steps above must draw outlines from this stacking context at this stage. (It is recommended to draw outlines in this step and not in the steps above.) E.3 Notes The background of the root element is only painted once, over the whole canvas. While the backgrounds of bidirectional inlines are painted in tree order, they are positioned in visual order. Since the positioning of inline backgrounds is unspecified in CSS 2.1, the exact result of these two requirements is UA-defined. CSS3 may define this in more detail. Appendix F. Full property table This appendix is informative, not normative. Name Values Initial value Applies to (Default: all) Inherited? Percentages (Default: N/A) Media groups 'azimuth' | [[ left-side | far-left | left | center-left | center | center-right | right | far-right | right-side ] || behind ] | leftwards | rightwards | inherit center yes aural 'background-attachment' scroll | fixed | inherit scroll no visual 'background-color' | transparent | inherit transparent no visual 'background-image' | none | inherit none no visual 'background-position' [ [ | | left | center | right ] [ | | top | center | bottom ]? ] | [ [ left | center | right ] || [ top | center | bottom ] ] | inherit 0% 0% no refer to the size of the box itself visual 'background-repeat' repeat | repeat-x | repeat-y | no-repeat | inherit repeat no visual 'background' ['background-color' || 'background-image' || 'background-repeat' || 'background-attachment' || 'background-position'] | inherit see individual properties no allowed on 'background-position' visual 'border-collapse' collapse | separate | inherit separate 'table' and 'inline-table' elements yes visual 'border-color' [ | transparent ]{1,4} | inherit see individual properties no visual 'border-spacing' ? | inherit 0 'table' and 'inline-table' elements yes visual 'border-style' {1,4} | inherit see individual properties no visual 'border-top' 'border-right' 'border-bottom' 'border-left' [ || || 'border-top-color' ] | inherit see individual properties no visual 'border-top-color' 'border-right-color' 'border-bottom-color' 'border-left-color' | transparent | inherit the value of the 'color' property no visual 'border-top-style' 'border-right-style' 'border-bottom-style' 'border-left-style' | inherit none no visual 'border-top-width' 'border-right-width' 'border-bottom-width' 'border-left-width' | inherit medium no visual 'border-width' {1,4} | inherit see individual properties no visual 'border' [ || || 'border-top-color' ] | inherit see individual properties no visual 'bottom' | | auto | inherit auto positioned elements no refer to height of containing block visual 'caption-side' top | bottom | inherit top 'table-caption' elements yes visual 'clear' none | left | right | both | inherit none block-level elements no visual 'clip' | auto | inherit auto absolutely positioned elements no visual 'color' | inherit depends on user agent yes visual 'content' normal | none | [ | | | attr( ) | open-quote | close-quote | no-open-quote | no-close-quote ]+ | inherit normal :before and :after pseudo-elements no all 'counter-increment' [ ? ]+ | none | inherit none no all 'counter-reset' [ ? ]+ | none | inherit none no all 'cue-after' | none | inherit none no aural 'cue-before' | none | inherit none no aural 'cue' [ 'cue-before' || 'cue-after' ] | inherit see individual properties no aural 'cursor' [ [ ,]* [ auto | crosshair | default | pointer | move | e-resize | ne-resize | nw-resize | n-resize | se-resize | sw-resize | s-resize | w-resize | text | wait | help | progress ] ] | inherit auto yes visual, interactive 'direction' ltr | rtl | inherit ltr all elements, but see prose yes visual 'display' inline | block | list-item | inline-block | table | inline-table | table-row-group | table-header-group | table-footer-group | table-row | table-column-group | table-column | table-cell | table-caption | none | inherit inline no all 'elevation' | below | level | above | higher | lower | inherit level yes aural 'empty-cells' show | hide | inherit show 'table-cell' elements yes visual 'float' left | right | none | inherit none all, but see 9.7 no visual 'font-family' [[ | ] [, | ]* ] | inherit depends on user agent yes visual 'font-size' | | | | inherit medium yes refer to inherited font size visual 'font-style' normal | italic | oblique | inherit normal yes visual 'font-variant' normal | small-caps | inherit normal yes visual 'font-weight' normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | inherit normal yes visual 'font' [ [ 'font-style' || 'font-variant' || 'font-weight' ]? 'font-size' [ / 'line-height' ]? 'font-family' ] | caption | icon | menu | message-box | small-caption | status-bar | inherit see individual properties yes see individual properties visual 'height' | | auto | inherit auto all elements but non-replaced inline elements, table columns, and column groups no see prose visual 'left' | | auto | inherit auto positioned elements no refer to width of containing block visual 'letter-spacing' normal | | inherit normal yes visual 'line-height' normal | | | | inherit normal yes refer to the font size of the element itself visual 'list-style-image' | none | inherit none elements with 'display: list-item' yes visual 'list-style-position' inside | outside | inherit outside elements with 'display: list-item' yes visual 'list-style-type' disc | circle | square | decimal | decimal-leading-zero | lower-roman | upper-roman | lower-greek | lower-latin | upper-latin | armenian | georgian | lower-alpha | upper-alpha | none | inherit disc elements with 'display: list-item' yes visual 'list-style' [ 'list-style-type' || 'list-style-position' || 'list-style-image' ] | inherit see individual properties elements with 'display: list-item' yes visual 'margin-right' 'margin-left' | inherit 0 all elements except elements with table display types other than table-caption, table and inline-table no refer to width of containing block visual 'margin-top' 'margin-bottom' | inherit 0 all elements except elements with table display types other than table-caption, table and inline-table no refer to width of containing block visual 'margin' {1,4} | inherit see individual properties all elements except elements with table display types other than table-caption, table and inline-table no refer to width of containing block visual 'max-height' | | none | inherit none all elements but non-replaced inline elements, table columns, and column groups no see prose visual 'max-width' | | none | inherit none all elements but non-replaced inline elements, table rows, and row groups no refer to width of containing block visual 'min-height' | | inherit 0 all elements but non-replaced inline elements, table columns, and column groups no see prose visual 'min-width' | | inherit 0 all elements but non-replaced inline elements, table rows, and row groups no refer to width of containing block visual 'orphans' | inherit 2 block container elements yes visual, paged 'outline-color' | invert | inherit invert no visual, interactive 'outline-style' | inherit none no visual, interactive 'outline-width' | inherit medium no visual, interactive 'outline' [ 'outline-color' || 'outline-style' || 'outline-width' ] | inherit see individual properties no visual, interactive 'overflow' visible | hidden | scroll | auto | inherit visible block containers no visual 'padding-top' 'padding-right' 'padding-bottom' 'padding-left' | inherit 0 all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column no refer to width of containing block visual 'padding' {1,4} | inherit see individual properties all elements except table-row-group, table-header-group, table-footer-group, table-row, table-column-group and table-column no refer to width of containing block visual 'page-break-after' auto | always | avoid | left | right | inherit auto block-level elements (but see text) no visual, paged 'page-break-before' auto | always | avoid | left | right | inherit auto block-level elements (but see text) no visual, paged 'page-break-inside' avoid | auto | inherit auto block-level elements (but see text) no visual, paged 'pause-after' | | inherit 0 no see prose aural 'pause-before' | | inherit 0 no see prose aural 'pause' [ [ | ]{1,2} ] | inherit see individual properties no see descriptions of 'pause-before' and 'pause-after' aural 'pitch-range' | inherit 50 yes aural 'pitch' | x-low | low | medium | high | x-high | inherit medium yes aural 'play-during' [ mix || repeat ]? | auto | none | inherit auto no aural 'position' static | relative | absolute | fixed | inherit static no visual 'quotes' [ ]+ | none | inherit depends on user agent yes visual 'richness' | inherit 50 yes aural 'right' | | auto | inherit auto positioned elements no refer to width of containing block visual 'speak-header' once | always | inherit once elements that have table header information yes aural 'speak-numeral' digits | continuous | inherit continuous yes aural 'speak-punctuation' code | none | inherit none yes aural 'speak' normal | none | spell-out | inherit normal yes aural 'speech-rate' | x-slow | slow | medium | fast | x-fast | faster | slower | inherit medium yes aural 'stress' | inherit 50 yes aural 'table-layout' auto | fixed | inherit auto 'table' and 'inline-table' elements no visual 'text-align' left | right | center | justify | inherit a nameless value that acts as 'left' if 'direction' is 'ltr', 'right' if 'direction' is 'rtl' block containers yes visual 'text-decoration' none | [ underline || overline || line-through || blink ] | inherit none no (see prose) visual 'text-indent' | | inherit 0 block containers yes refer to width of containing block visual 'text-transform' capitalize | uppercase | lowercase | none | inherit none yes visual 'top' | | auto | inherit auto positioned elements no refer to height of containing block visual 'unicode-bidi' normal | embed | bidi-override | inherit normal all elements, but see prose no visual 'vertical-align' baseline | sub | super | top | text-top | middle | bottom | text-bottom | | | inherit baseline inline-level and 'table-cell' elements no refer to the 'line-height' of the element itself visual 'visibility' visible | hidden | collapse | inherit visible yes visual 'voice-family' [[ | ],]* [ | ] | inherit depends on user agent yes aural 'volume' | | silent | x-soft | soft | medium | loud | x-loud | inherit medium yes refer to inherited value aural 'white-space' normal | pre | nowrap | pre-wrap | pre-line | inherit normal yes visual 'widows' | inherit 2 block container elements yes visual, paged 'width' | | auto | inherit auto all elements but non-replaced inline elements, table rows, and row groups no refer to width of containing block visual 'word-spacing' normal | | inherit normal yes visual 'z-index' auto | | inherit auto positioned elements no visual Appendix G. Grammar of CSS 2.1 Contents * G.1 Grammar * G.2 Lexical scanner * G.3 Comparison of tokenization in CSS 2.1 and CSS1 * G.4 Implementation note This appendix is non-normative. The grammar below defines the syntax of CSS 2.1. It is in some sense, however, a superset of CSS 2.1 as this specification imposes additional semantic constraints not expressed in this grammar. A conforming UA must also adhere to the forward-compatible parsing rules, the selectors notation, the property and value notation, and the unit notation. However, not all syntactically correct CSS can take effect, since the document language may impose restrictions that are not in CSS, e.g., HTML imposes restrictions on the possible values of the "class" attribute. G.1 Grammar The grammar below is LALR(1) (but note that most UA's should not use it directly, since it does not express the parsing conventions, only the CSS 2.1 syntax). The format of the productions is optimized for human consumption and some shorthand notation beyond Yacc (see [YACC]) is used: * *: 0 or more * +: 1 or more * ?: 0 or 1 * |: separates alternatives * [ ]: grouping The productions are: stylesheet : [ CHARSET_SYM STRING ';' ]? [S|CDO|CDC]* [ import [ CDO S* | CDC S* ]* ]* [ [ ruleset | media | page ] [ CDO S* | CDC S* ]* ]* ; import : IMPORT_SYM S* [STRING|URI] S* media_list? ';' S* ; media : MEDIA_SYM S* media_list '{' S* ruleset* '}' S* ; media_list : medium [ COMMA S* medium]* ; medium : IDENT S* ; page : PAGE_SYM S* pseudo_page? '{' S* declaration? [ ';' S* declaration? ]* '}' S* ; pseudo_page : ':' IDENT S* ; operator : '/' S* | ',' S* ; combinator : '+' S* | '>' S* ; unary_operator : '-' | '+' ; property : IDENT S* ; ruleset : selector [ ',' S* selector ]* '{' S* declaration? [ ';' S* declaration? ]* '}' S* ; selector : simple_selector [ combinator selector | S+ [ combinator? selector ]? ]? ; simple_selector : element_name [ HASH | class | attrib | pseudo ]* | [ HASH | class | attrib | pseudo ]+ ; class : '.' IDENT ; element_name : IDENT | '*' ; attrib : '[' S* IDENT S* [ [ '=' | INCLUDES | DASHMATCH ] S* [ IDENT | STRING ] S* ]? ']' ; pseudo : ':' [ IDENT | FUNCTION S* [IDENT S*]? ')' ] ; declaration : property ':' S* expr prio? ; prio : IMPORTANT_SYM S* ; expr : term [ operator? term ]* ; term : unary_operator? [ NUMBER S* | PERCENTAGE S* | LENGTH S* | EMS S* | EXS S* | ANGLE S* | TIME S* | FREQ S* ] | STRING S* | IDENT S* | URI S* | hexcolor | function ; function : FUNCTION S* expr ')' S* ; /* * There is a constraint on the color that it must * have either 3 or 6 hex-digits (i.e., [0-9a-fA-F]) * after the "#"; e.g., "#000" is OK, but "#abcd" is not. */ hexcolor : HASH S* ; G.2 Lexical scanner The following is the tokenizer, written in Flex (see [FLEX]) notation. The tokenizer is case-insensitive. The "\377" represents the highest character number that current versions of Flex can deal with (decimal 255). It should be read as "\4177777" (decimal 1114111), which is the highest possible code point in Unicode/ISO-10646. %option case-insensitive h [0-9a-f] nonascii [\240-\377] unicode \\{h}{1,6}(\r\n|[ \t\r\n\f])? escape {unicode}|\\[^\r\n\f0-9a-f] nmstart [_a-z]|{nonascii}|{escape} nmchar [_a-z0-9-]|{nonascii}|{escape} string1 \"([^\n\r\f\\"]|\\{nl}|{escape})*\" string2 \'([^\n\r\f\\']|\\{nl}|{escape})*\' badstring1 \"([^\n\r\f\\"]|\\{nl}|{escape})*\\? badstring2 \'([^\n\r\f\\']|\\{nl}|{escape})*\\? badcomment1 \/\*[^*]*\*+([^/*][^*]*\*+)* badcomment2 \/\*[^*]*(\*+[^/*][^*]*)* baduri1 url\({w}([!#$%&*-\[\]-~]|{nonascii}|{escape})*{w} baduri2 url\({w}{string}{w} baduri3 url\({w}{badstring} comment \/\*[^*]*\*+([^/*][^*]*\*+)*\/ ident -?{nmstart}{nmchar}* name {nmchar}+ num [0-9]+|[0-9]*"."[0-9]+ string {string1}|{string2} badstring {badstring1}|{badstring2} badcomment {badcomment1}|{badcomment2} baduri {baduri1}|{baduri2}|{baduri3} url ([!#$%&*-~]|{nonascii}|{escape})* s [ \t\r\n\f]+ w {s}? nl \n|\r\n|\r|\f A a|\\0{0,4}(41|61)(\r\n|[ \t\r\n\f])? C c|\\0{0,4}(43|63)(\r\n|[ \t\r\n\f])? D d|\\0{0,4}(44|64)(\r\n|[ \t\r\n\f])? E e|\\0{0,4}(45|65)(\r\n|[ \t\r\n\f])? G g|\\0{0,4}(47|67)(\r\n|[ \t\r\n\f])?|\\g H h|\\0{0,4}(48|68)(\r\n|[ \t\r\n\f])?|\\h I i|\\0{0,4}(49|69)(\r\n|[ \t\r\n\f])?|\\i K k|\\0{0,4}(4b|6b)(\r\n|[ \t\r\n\f])?|\\k L l|\\0{0,4}(4c|6c)(\r\n|[ \t\r\n\f])?|\\l M m|\\0{0,4}(4d|6d)(\r\n|[ \t\r\n\f])?|\\m N n|\\0{0,4}(4e|6e)(\r\n|[ \t\r\n\f])?|\\n O o|\\0{0,4}(4f|6f)(\r\n|[ \t\r\n\f])?|\\o P p|\\0{0,4}(50|70)(\r\n|[ \t\r\n\f])?|\\p R r|\\0{0,4}(52|72)(\r\n|[ \t\r\n\f])?|\\r S s|\\0{0,4}(53|73)(\r\n|[ \t\r\n\f])?|\\s T t|\\0{0,4}(54|74)(\r\n|[ \t\r\n\f])?|\\t U u|\\0{0,4}(55|75)(\r\n|[ \t\r\n\f])?|\\u X x|\\0{0,4}(58|78)(\r\n|[ \t\r\n\f])?|\\x Z z|\\0{0,4}(5a|7a)(\r\n|[ \t\r\n\f])?|\\z %% {s} {return S;} \/\*[^*]*\*+([^/*][^*]*\*+)*\/ /* ignore comments */ {badcomment} /* unclosed comment at EOF */ "" {return CDC;} "~=" {return INCLUDES;} "|=" {return DASHMATCH;} {string} {return STRING;} {badstring} {return BAD_STRING;} {ident} {return IDENT;} "#"{name} {return HASH;} @{I}{M}{P}{O}{R}{T} {return IMPORT_SYM;} @{P}{A}{G}{E} {return PAGE_SYM;} @{M}{E}{D}{I}{A} {return MEDIA_SYM;} "@charset " {return CHARSET_SYM;} "!"({w}|{comment})*{I}{M}{P}{O}{R}{T}{A}{N}{T} {return IMPORTANT_SYM;} {num}{E}{M} {return EMS;} {num}{E}{X} {return EXS;} {num}{P}{X} {return LENGTH;} {num}{C}{M} {return LENGTH;} {num}{M}{M} {return LENGTH;} {num}{I}{N} {return LENGTH;} {num}{P}{T} {return LENGTH;} {num}{P}{C} {return LENGTH;} {num}{D}{E}{G} {return ANGLE;} {num}{R}{A}{D} {return ANGLE;} {num}{G}{R}{A}{D} {return ANGLE;} {num}{M}{S} {return TIME;} {num}{S} {return TIME;} {num}{H}{Z} {return FREQ;} {num}{K}{H}{Z} {return FREQ;} {num}{ident} {return DIMENSION;} {num}% {return PERCENTAGE;} {num} {return NUMBER;} "url("{w}{string}{w}")" {return URI;} "url("{w}{url}{w}")" {return URI;} {baduri} {return BAD_URI;} {ident}"(" {return FUNCTION;} . {return *yytext;} G.3 Comparison of tokenization in CSS 2.1 and CSS1 There are some differences in the syntax specified in the CSS1 recommendation ([CSS1]), and the one above. Most of these are due to new tokens in CSS2 that did not exist in CSS1. Others are because the grammar has been rewritten to be more readable. However, there are some incompatible changes, that were felt to be errors in the CSS1 syntax. They are explained below. * CSS1 style sheets could only be in 1-byte-per-character encodings, such as ASCII and ISO-8859-1. CSS 2.1 has no such limitation. In practice, there was little difficulty in extrapolating the CSS1 tokenizer, and some UAs have accepted 2-byte encodings. * CSS1 only allowed four hex-digits after the backslash (\) to refer to Unicode characters, CSS2 allows six. Furthermore, CSS2 allows a white space character to delimit the escape sequence. E.g., according to CSS1, the string "\abcdef" has 3 letters (\abcd, e, and f), according to CSS2 it has only one (\abcdef). * The tab character (ASCII 9) was not allowed in strings. However, since strings in CSS1 were only used for font names and for URLs, the only way this can lead to incompatibility between CSS1 and CSS2 is if a style sheet contains a font family that has a tab in its name. * Similarly, newlines (escaped with a backslash) were not allowed in strings in CSS1. * CSS2 parses a number immediately followed by an identifier as a DIMENSION token (i.e., an unknown unit), CSS1 parsed it as a number and an identifier. That means that in CSS1, the declaration 'font: 10pt/1.2serif' was correct, as was 'font: 10pt/12pt serif'; in CSS2, a space is required before "serif". (Some UAs accepted the first example, but not the second.) * In CSS1, a class name could start with a digit (".55ft"), unless it was a dimension (".55in"). In CSS2, such classes are parsed as unknown dimensions (to allow for future additions of new units). To make ".55ft" a valid class, CSS2 requires the first digit to be escaped (".\35 5ft") G.4 Implementation note The lexical scanner for the CSS core syntax in section 4.1.1 can be implemented as a scanner without back-up. In Lex notation, that requires the addition of the following patterns (which do not change the returned tokens, only the efficiency of the scanner): {ident}/\\ return IDENT; #{name}/\\ return HASH; @{ident}/\\ return ATKEYWORD; #/\\ return DELIM; @/\\ return DELIM; @/- return DELIM; @/-\\ return DELIM; -/\\ return DELIM; -/- return DELIM; \, 1, 2 + definition of, 1 * anonymous, 1 * anonymous boxes., 1 * anonymous inline boxes, 1 * armenian, 1 * at-rule, 1 * at-rules, 1 * atomic inline-level box, 1 * attr(), 1 * attribute, 1 * 'audio' media group, 1 * auditory icon, 1 * Author, 1 * authoring tool, 1 * automatic numbering, 1 * 'azimuth', 1 * 'background', 1 * 'background-attachment', 1 * 'background-color', 1 * 'background-image', 1 * 'background-position', 1 * 'background-repeat', 1 * backslash escapes, 1 * before, 1 * bidirectionality (bidi), 1 * 'bitmap' media group, 1 * block, 1 * block box, 1 * block container box, 1 * 'block', definition of, 1 * block-level box, 1 * block-level element, 1 * BOM, 1 * border box, 1 * border edge, 1 * 'border', 1 * 'border-bottom', 1 * 'border-bottom-color', 1 * 'border-bottom-style', 1 * 'border-bottom-width', 1 * 'border-collapse', 1 * 'border-color', 1 * 'border-left', 1 * 'border-left-color', 1 * 'border-left-style', 1 * 'border-left-width', 1 * 'border-right', 1 * 'border-right-color', 1 * 'border-right-style', 1 * 'border-right-width', 1 * 'border-spacing', 1 * , 1 * , definition of, 1 * 'border-style', 1 * 'border-top', 1 * 'border-top-color', 1 * 'border-top-style', 1 * 'border-top-width', 1 * + definition of, 1 * 'border-width', 1 * border + of a box, 1 * + definition of, 1 * 'bottom', 1 * box + border, 1 + content, 1 + content height, 1 + content width, 1 + margin, 1 + overflow, 1 + padding, 1 * canvas, 1, 2 * 'caption-side', 1 * cascade, 1 * case sensitivity, 1 * character encoding, 1 + default, 1 + user agent's determination of, 1 * child, 1 * child selector, 1 * circle, 1 * 'clear', 1 * clearance, 1 * 'clip', 1 * clipping region, 1 * close-quote, 1, 2 * collapse, 1 * collapse through, 1 * collapsing margin, 1 * color, 1 * , 1, 2 + definition of, 1 * 'color', 1 * combinator, 1 * comments, 1 * computed value, 1 * conditional import, 1 * conformance, 1, 2 * consecutive, 1 * containing block, 1, 2, 3 + initial, 1 * content, 1 * content box, 1 * content edge, 1 * 'content', 1 * content + of a box, 1 + rendered, 1 * 'continuous' media group, 1 * , 1 * , definition of, 1 * counter(), 1 * 'counter-increment', 1 * 'counter-reset', 1 * counters, 1 * 'cue', 1 * 'cue-after', 1 * 'cue-before', 1 * cursive, definition of, 1 * 'cursor', 1 * 'dashed', 1, 2 * decimal, 1 * decimal-leading-zero, 1 * declaration, 1 * declaration block, 1 * default style sheet, 1 * default + character encoding, 1 * descendant, 1 * descendant-selectors, 1 * 'direction', 1 * disc, 1 * 'display', 1 * document language, 1 * document tree, 1 * 'dotted', 1, 2 * 'double', 1, 2 * drop caps, 1 * DTD, 1, 2 * element, 1 + following, 1 + preceding, 1 * 'elevation', 1 * em (unit), 1 * empty, 1 * 'empty-cells', 1 * ex (unit), 1 * exact matching, 1 * fantasy, definition of, 1 * fictional tag sequence, 1, 2, 3 * first-child, 1 * first-letter, 1 * first-line, 1 * float rules, 1 * 'float', 1 * flow of an element, 1 * focus, 1 * focus (pseudo-class), 1 * following element, 1 * 'font', 1 * 'font-family', 1 * 'font-size', 1 * 'font-style', 1 * 'font-variant', 1 * 'font-weight', 1 * formatting context, 1 * formatting structure, 1 * forward-compatible parsing, 1 * , 1 + definition of, 1 * generated content, 1 * , definition of, 1 * georgian, 1 * 'grid' media group, 1 * 'groove', 1, 2 * 'height', 1 * 'hidden, 1 * 'hidden', 1 * hover (pseudo-class), 1 * hyphen-separated matching, 1 * identifier, 1 * identifier, definition of, 1 * ignore, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 * in-flow, 1 * inherit, definition of, 1 * initial caps, 1 * initial containing block, 1 * initial value, 1 * inline box, 1 * 'inline', definition of, 1 * 'inline-block', definition of, 1 * inline-level box, 1 * inline-level element, 1 * inline-table, 1 * inner edge, 1 * 'inset', 1, 2 * , 1 + definition of, 1 * 'interactive media group, 1 * internal table box, 1 * internal table element, 1 * intrinsic dimensions, 1 * invert, 1 * iso-10646, 1 * LALR(1), 1 * lang (pseudo-class), 1 * language (human), 1 * language code, 1 * + definition of, 1 * 'left', 1 * , 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 + definition of, 1 * 'letter-spacing', 1 * ligatures, 1 * line box, 1 * line-box, 1 * 'line-height', 1 * link (pseudo-class), 1 * list properties, 1 * 'list-item', definition of, 1 * 'list-style', 1 * 'list-style-image', 1 * 'list-style-position', 1 * 'list-style-type', 1 * lower-greek, 1 * lower-latin, 1 * lower-roman, 1 * mapping elements to table parts, 1 * margin box, 1 * margin edge, 1 * 'margin', 1 * 'margin-bottom', 1 * 'margin-left', 1 * 'margin-right', 1 * 'margin-top', 1 * + definition of, 1 * margin + of a box, 1 * match, 1 * 'max-height', 1 * 'max-width', 1 * MAY, 1 * media, 1 * media group, 1 * media-dependent import, 1 * message entity, 1 * 'min-height', 1 * 'min-width', 1 * monospace, definition of, 1 * multiple declarations, 1 * MUST, 1 * MUST NOT, 1 * newline, 1 * no-close-quote, 1, 2 * no-open-quote, 1, 2 * none, 1 * 'none' + as border style, 1, 2 + as display value, 1 * normal, 1 * , 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 + definition of, 1 * open-quote, 1, 2 * OPTIONAL, 1 * 'orphans', 1 * out of flow, 1 * outer edge, 1 * outline, 1 * 'outline', 1 * 'outline-color', 1 * 'outline-style', 1 * 'outline-width', 1 * 'outset', 1, 2 * overflow, 1 * 'overflow', 1 * padding box, 1 * padding edge, 1 * 'padding', 1 * 'padding-bottom', 1 * 'padding-left', 1 * 'padding-right', 1 * 'padding-top', 1 * + definition of, 1 * padding + of a box, 1 * page area, 1 * page box, 1 * page selector, 1 * 'page-break-after', 1 * 'page-break-before', 1 * 'page-break-inside', 1 * page-context, 1 * 'paged' media group, 1 * parent, 1 * 'pause', 1 * 'pause-after', 1 * 'pause-before', 1 * , 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 + definition of, 1 * 'pitch', 1 * 'pitch-range', 1 * pixel, 1 * 'play-during', 1 * 'position', 1 * positioned element/box, 1 * positioning scheme, 1 * preceding element, 1 * principal block-level box, 1 * proper table child, 1 * proper table row parent, 1 * Property, 1 * property, 1 * 'property-name', 1 * pseudo-class + :first, 1 + :left, 1 + :right, 1 * pseudo-classes, 1 + :active, 1 + :focus, 1 + :hover, 1 + :lang, 1 + :link, 1 + :visited, 1 * pseudo-elements, 1 + :after, 1, 2 + :before, 1, 2 + :first-letter, 1 + :first-line, 1, 2 * quad width, 1 * 'quotes', 1 * RECOMMENDED, 1 * reference pixel, 1 * relative positioning, 1 * relative units, 1 * rendered content, 1 * replaced element, 1 * REQUIRED, 1 * 'richness', 1 * 'ridge', 1, 2 * + definition of, 1 * 'right', 1 * root, 1 * row group box, 1 * row groups, 1 * rule sets, 1 * run-in, 1 * sans-serif, definition of, 1 * scope, 1 * screen reader, 1 * selector, 1, 2, 3, 4 + match, 1 + subject of, 1 * separated borders, 1 * serif, definition of, 1 * SHALL, 1 * SHALL NOT, 1 * + definition of, 1 * sheet, 1 * shorthand property, 1, 2, 3 * SHOULD, 1 * SHOULD NOT, 1 * sibling, 1 * simple selector, 1 * 'solid', 1, 2 * source document, 1 * space-separated matching, 1 * 'speak', 1 * 'speak-header', 1 * 'speak-numeral', 1 * 'speak-punctuation', 1 * + definition of, 1 * specified value, 1 * 'speech' media group, 1 * 'speech-rate', 1 * square, 1 * stack level, 1 * stacking context, 1 * statements, 1 * 'static' media group, 1 * 'stress', 1 * string, 1 * , 1, 2, 3 * , definition of, 1 * illegal, 1 * style sheet, 1 * subject (of selector), 1 * system fonts, 1 * table, 1 * table element, 1 + internal, 1 * table-caption, 1 * table-cell, 1 * table-column, 1 * table-column-group, 1 * table-footer-group, 1 * table-header-group, 1 * 'table-layout', 1 * table-row, 1 * table-row-group, 1 * tables, 1 * tabular container, 1 * 'tactile' media group, 1 * 'text-align', 1 * 'text-decoration', 1 * 'text-indent', 1 * 'text-transform', 1 * text/css, 1 * , 1 + definition of, 1 * tokenizer, 1 * + definition of, 1 * 'top', 1 * type selector, 1 * UA, 1 * unicode, 1 * 'unicode-bidi', 1 * universal selector, 1 * upper-latin, 1 * upper-roman, 1 * , 1, 2, 3, 4, 5, 6, 7 + definition of, 1 * used value, 1 * User, 1 * user agent, 1 * User agent (UA), 1 * UTF-8, 1 * valid style sheet, 1 * validity, 1 * value, 1 * 'vertical-align', 1 * viewport, 1 * 'visibility', 1 * visited (pseudo-class), 1 * visual formatting model, 1 * 'visual' media group, 1 * 'voice-family', 1 * volume, 1 * 'volume', 1 * 'white-space', 1 * 'widows', 1 * 'width', 1 * 'word-spacing', 1 * x-height, 1 * 'z-index', 1Help, help! I am under a hat! âGwieF
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