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Table of Contents

1. Introduction

This section is not normative.

Web developers, design tools and design system developers often use color functions to assist in scaling the design of their component color relations. With the increasing usage of design systems that support multiple platforms and multiple user preferences, like the increased capability of Dark Mode in UI, this becomes even more useful to not need to manually set color, and to instead have a single source from which schemes are calculated.

Currently Sass, calc() on HSL values, or PostCSS is used to do this. However, preprocessors are unable to work on dynamically adjusted colors; all current solutions are restricted to the sRGB gamut and to the perceptual limitations of HSL (colors are bunched up in the color wheel, and two colors with visually different lightness, like yellow and blue, can have the same HSL lightness).

This module adds three functions: color-mix(), color-contrast(), and a way to modify colors.

The perceptually uniform ``lch()`` color space is used for mixing by default, as this has no gamut restrictions and colors are evenly distributed. However, other color spaces can be specified, including ``hsl()`` or ``srgb`` if desired.

2. Color Spaces

Mixing or otherwise combining colors has different results depending on the color space used. In some cases, the result of physically mixing two colored lights is desired (in that case, the CIE XYZ color space is appropriate, because it is linear in light intensity). In other cases, colors which are evenly spaced perceptually are desired (in which case, the CIE Lab color space is designed to be perceptually uniform). Alternatively, maximizing chroma so that color mixtures follow along the hue wheel is wanted (CIE LCH works well for this). Lastly, compatibility with legacy Web content may be the most important consideration. (the sRGB color space, which is neither linear-light nor perceptually uniform, is the choice here).

<color-space> = srgb | hsl | hwb | xyz | lab | lch

The srgb, hsl, hwb, xyz, lab, and lch keywords each refer to their corresponding color space.

When no <color-space> is specified, the mixing is done in the lch color space. The xyz color space is CIE XYZ, with a D50 whitepoint, and allows computation to be done in a linear-light-intensity space.

3. Mixing colors: the color-mix() function

This function takes two <color> specifications and returns the result of mixing them, in a given <color-space>, by a specified amount.

color-mix() = color-mix( in <color-space> , [ <color> && <percentage [0,100]>? ]#{2} <hue-adjuster>?)
<hue-adjuster> = shorter | longer | increasing | decreasing | specified

Percentages are required to be in the range 0% to 100%. Negative percentages are specifically disallowed. The percentages are normalized as follows:

1. Let p1 be the first percentage and p2 the second one.

2. If both percentages are omitted, they each default to 50% (an equal mix of the two colors).

3. Otherwise, if p2 is omitted, it becomes 100% - p1

4. Otherwise, if p1 is omitted, it becomes 100% - p2

5. If the percentages sum to zero, the function is invalid.

6. Otherwise, if both are provided and add up to greater than 100%, they are scaled accordingly so that they add up to 100%.

7. Otherwise, if both are provided and add up to less than 100%, the sum is saved as an alpha multiplier. They are then scaled accordingly so that they add up to 100%.

This means that p1 becomes p1 / (p1 + p2) and p2 becomes p2 / (p1 + p2).

color-mix(in lch, purple 50%, plum 50%)color-mix(in lch, purple 50%, plum)color-mix(in lch, purple, plum 50%)color-mix(in lch, purple, plum)color-mix(in lch, plum, purple)color-mix(in lch, purple 80%, plum 80%)

color-mix(in lch, purple 30%, plum 30%)

After normalizing both percentages, the result is produced via the following algorithm:

1. Both colors are converted to the specified <color-space>. If the specified color space has a smaller gamut than the one in which the color to be adjusted is specified, gamut mapping will occur.

2. Colors are then interpolated in the specified color space, as described in CSS Color 4 §13 Interpolation. If the specified color space is a cylindrical-polar-color space, then the <hue-adjuster> controls the interpolation of hue, as described in CSS Color 4 §13.3 Hue interpolation. If no <hue-adjuster> is specified, it is as if shorter had been specified. If the specified colorspace is a rectangular-orthogonal-color space, then specifying a <hue-adjuster> is not an error, but has no effect.

3. If an alpha multiplier was produced during percentage normalization, the alpha component of the interpolated result is multiplied by the alpha multiplier.

The result of mixing is the color at the specified percentage along the progression of the second color to the first color.

Note: As a corrollary, a percentage of 0% just returns the other color converted to the specified color space, and a percentage of 100% returns the same color converted to the specified color space.

This example produces a mixture of 40% peru and 60% palegoldenrod.

color-mix(in lch, peru 40%, palegoldenrod)

The mixing is done in lch() color space. Here is a top-down view, looking along the neutral L axis:

Mixtures of peru and palegoldenrod. Peru has a hue angle, measured from the positive a axis, of 63.677 degrees while palegoldenrod has a hue angle of 98.834 degrees. Peru has a chroma, or distance from the central neutral axis, of 54.011 while palegoldenrod has a chroma of 31.406. Mixtures lie along the curve. A 40%/60% mixture is shown.

The calculation is as follows:

• peru is lch(62.253% 54.011 63.677)

• palegoldenrod is lch(91.374% 31.406 98.834)

• the mixed lightness is 62.253 * 40/100 + 91.374 * (100-40)/100 = 79.7256

• the mixed chroma is 54.011 * 40/100 + 31.406 * (100-40)/100 = 40.448

• the mixed hue is 63.677 * 40/100 + 98.834 * (100-40)/100 = 84.771

• the mixed result is lch(79.7256% 40.448 84.771)

This example produces the mixture of teal and olive, in lch color space (the default), with each lch channel being 65% of the value for teal and 35% of the value for olive.

Note: interpolating on hue and chroma keeps the intermediate colors as saturated as the endpoint colors.

color-mix(in lch, teal 65%, olive);

Mixtures of teal and olive. Teal has a hue angle, measured from the positive a axis, of 196.4524 degrees while olive has a hue angle of 99.5746 degrees. Teal has a chroma, or distance from the central neutral axis, of 31.6903 while olive has a chroma of 56.8124. Mixtures lie along the dashed curve. A 65%/35% mixture is shown.

The calculation is as follows:

• sRGB teal (#008080) is lch(47.9855% 31.6903 196.4524)

• sRGB olive (#808000) is lch(52.1496% 56.8124 99.5746)

• mixed lightness is 47.9855 * 0.65 + 52.1496 * 0.35 = 49.4429

• mixed chroma is 31.6903 * 0.65 + 56.8124 * 0.35 = 40.4830

• mixed hue is 196.4524 * 0.65 + 99.5746 * 0.35 = 162.5452

• mixed result is lch(49.4429% 40.4830 162.5452)

• which is a slightly-blueish green: rgb(7.7377% 52.5730% 37.3213%)

The choice of mixing colorspace can have a large effect on the end result.

color-mix(in lch, white, black);color-mix(in xyz, white, black);color-mix(in srgb, white, black);

4. Selecting the most contrasting color: the color-contrast() function

This function takes, firstly, a single color (typically a background, but not necessarily), secondly, a list of two or more colors, and thirdly, an optional target luminance contrast [WCAG21]. It selects from that list the first color color to meet or exceed the target contrast. If no target is specified, it selects the first color with the highest contrast to the single color.

The single color is separated from the list with the keyword vs and the target contrast, if present, is separated from the list with the keyword to.

color-contrast() = color-contrast( <color> vs <color>#{2,}  [ to [<number> | AA | AA-large | AAA | AAA-large]]? )

The keyword AA is equivalent to 4.5, AA-large is equivalent to 3, AAA is equivalent to 7, and AAA-large is equivalent to 4.5 .

color-contrast(wheat vs tan, sienna,var(--myAccent), #d2691e)

color-contrast(wheat vs bisque, darkgoldenrod, olive, sienna, darkgreen, maroon to AA)

color-contrast(wheat vs bisque, darkgoldenrod, olive, sienna, darkgreen, maroon to 5.8)

The colors in the list (after the keyword vs) are tested sequentially, from left to right; a color is the temporary winner if it has the highest contrast of all those tested so far.

List traversal is terminated once the target contrast has been met or exceeded.

Once the end of the list is reached, if there is no target contrast, the current temporary winner is the overall winner. Thus, if two colors in the list happen to have the same contrast, the earlier in the list wins because the later one has the same contrast, not higher.

If there is a target contrast, and the end of the list is reached without meeting that target, either white or black is returned, whichever has the higher contrast.

color-contrast(wheat vs bisque, darkgoldenrod, olive to AA)

foo {--bg:hsl(20050%80%);--purple-in-hsl:hsl(300100%25%);color:color-contrast(var(--bg) vs hsl(20083%23%), purple,var(--purple-in-hsl));}

5. Modifying colors

Note: There are currently two proposals for modifying colors: color-adjust and Relative color syntax.

there are two proposals for color modification (proposal 1, proposal 2). The CSS WG expects that the best aspects of each will be chosen to produce a single eventual solution. <https://github.com/w3c/csswg-drafts/issues/3187>

5.1. Adjusting colors: the color-adjust function

This function takes one <color> specification and returns the result of adjusting that color, in a given color space, by a specified color-adjuster.

Unless otherwise specified, the adjustment is done in the lch color space.

Multiple color functions can be specified.

color-adjust() = color-adjust( <color> <color-adjuster> && [ in <color-space> ]?  )

<color-adjuster> = [ [
      <srgb-adjuster> | <hsl-adjuster> | <hwb-adjuster>
    | <xyz-adjuster> | <lab-adjuster> | <lch-adjuster>
  ] | alpha ] <percentage>
<srgb-adjuster> = red | green | blue
<hsl-adjuster> = hue | saturation | lightness
<hwb-adjuster> = hue |  whiteness | blackness
<xyz-adjuster> = x | y | z
<lab-adjuster> = lightness | a | b
<lch-adjuster> = lightness | chroma | hue

The meaning of the adjusters is defined by color space. For example, if the <color-space> is hsl, hue means the HSL hue, which is not the same as the LCH hue; if the color space is lch, lightness means the LCH Lightness, which is the same as Lab lightness, but different to the HSL Lightness.

Only the <color-adjuster>s defined for a given <color-space> are available. For example, it is not possible to use the HWB whiteness adjuster unless the color space is hwb. The alpha adjuster is available on any <color-space>.

Note: not all <color-adjuster>s are equally useful. Adjustments in LCH are the most useful, which is why it is the default. Adjustments on the a and b axes are rarely needed. Adjustments in the srgb-related spaces (srgb itself, hsl, hwb) are provided mainly for backward compatibility with the sorts of adjustments currently done in CSS preprocessors. Adjusting the individual x, y and z channels will produce significant hue shifts; however, adjusting all three channels together is useful and will lighten or darken the color.

color-adjust(peru lightness -20%);

5.2. Relative color syntax

In previous levels of this specification, the color functions could only specify colors in an absolute manner, by directly specifying all of the color channels.

The new relative color syntax allows existing colors to be modified using the color functions: if an origin color is specified, then each color channel can either be directly specified, or taken from the origin color (and possibly modified with math functions).

The precise details of each function’s changes to accomodate relative colors are listed below, but they all follow a common structure:

• An origin color can be specified with a ''from <color>'' value at the start of the function.

• If an origin color is specified, the remaining arguments can either be specified directly, as normal, be specified as a channel keyword referring to one of the channels of the origin color. Math functions can also use these keywords to do dynamic modifications of the origin color’s channels.

• Relative color syntax doesn’t change whether an argument is required or optional. If the alpha value is omitted, however, it defaults to taking from the origin color (rather than defaulting to 100%, as it does in the absolute syntax).

If the origin color was originally specified with a different color function, it’s first converted into the chosen color function, so it has meaningful values for the channels.

html {--bg-color: blue;}
.overlay {background:rgb(from var(--bg-color) r g b / 80%);}

html {--color: green;}
.foo {--darker-accent:lch(from var(--color)calc(l / 2) c h);}

--blue-into-gray:rgb(from var(--color)calc(r * .3 + g * .59 + b * .11)calc(r * .3 + g * .59 + b * .11)calc(r * .3 + g * .59 + b * .11));

5.2.1. Relative RGB colors

The grammar of the rgb() function is extended as follows:

rgb() = rgb( <percentage>{3} [ / <alpha-value> ]? ) |
        rgb( <number>{3} [ / <alpha-value> ]? ) |
        rgb( [ from <color> ]? [ <number> | <percentage> ]{3} [ / <alpha-value> ]? )

Within a relative color syntax rgb() function, the allowed channel keywords are:

• r, g, and b are all <percentage>s that correspond to the origin color’s red, green, and blue channels after its conversion to sRGB

• alpha is a <percentage> that corresponds to the origin color’s alpha transparency

rgb(from  indianred 255 g b)

5.2.2. Relative HSL colors

The grammar of the hsl() function is extended as follows:

hsl() = hsl([from <color>]? <hue> <percentage> <percentage> [ / <alpha-value> ]? )

Within a relative color syntax hsl() function, the allowed channel keywords are:

• h is an <angle> that corresponds to the origin color’s HSL hue after its conversion to sRGB, normalized to a [0deg, 360deg) range

• s and l are <percentage>s that correspond to the origin color’s HSL saturation and lightness after its conversion to sRGB

• alpha is a <percentage> that corresponds to the origin color’s alpha transparency

--accent:  lightseagreen;
--complement:   hsl(from var(--accent) calc(h + 180deg) s l);

5.2.3. Relative HWB colors

The grammar of the hwb() function is extended as follows:

hwb() = hwb([from <color>]? <hue> <percentage> <percentage> [ / <alpha-value> ]? )

Within a relative color syntax hwb() function, the allowed channel keywords are:

• h is an <angle> that corresponds to the origin color’s HWB hue after its conversion to sRGB, normalized to a [0deg, 360deg) range

• w and b are <percentage>s that correspond to the origin color’s HWB whiteness and blackness after its conversion to sRGB

• alpha is a <percentage> that corresponds to the origin color’s alpha transparency

5.2.4. Relative Lab colors

The grammar of the lab() function is extended as follows:

lab() = lab([from <color>]? <percentage> <number> <number> [ / <alpha-value> ]? )

Within a relative color syntax lab() function, the allowed channel keywords are:

• l is a <percentage> that corresponds to the origin color’s CIE Lightness

• a and b are <number>s that correspond to the origin color’s CIELab a and b axises

• alpha is a <percentage> that corresponds to the origin color’s alpha transparency

--mycolor:  orchid;
// orchid is lab(62.753% 52.460 -34.103)
--mygray:  lab(from var(--mycolor) l 0 0)
// mygray is lab(62.753% 0 0) which is rgb(59.515% 59.515% 59.515%)

5.2.5. Relative LCH colors

The grammar of the lch() function is extended as follows:

lch() = lch([from <color>]? <percentage> <number> <hue> [ / <alpha-value> ]? )

Within a relative color syntax lch() function, the allowed channel keywords are:

• l is a <percentage> that corresponds to the origin color’s CIE Lightness

• c is a <number> that corresponds to the origin color’s LCH chroma

• h is an <angle> that corresponds to the origin color’s LCH hue, normalized to a [0deg, 360deg) range.

• alpha is a <percentage> that corresponds to the origin color’s alpha transparency

--accent:  lightseagreen;
--complement:   LCH(from var(--accent) l c calc(h + 180deg));

--mycolor:  orchid;
// orchid is lch(62.753% 62.571 326.973)
--mygray:  lch(from var(--mycolor) l 0 h)
// mygray is lch(62.753% 0 326.973) which is rgb(59.515% 59.515% 59.515%)

--mymuted:  lch(from var(--mygray) l 30 h);
// mymuted is lch(62.753% 30 326.973) which is rgb(72.710% 53.293% 71.224%)

5.2.6. Relative color-function colors

The grammar of the color() function is extended as follows:

color() = color( [from <color>]? <colorspace-params> [ / <alpha-value> ]? )
colorspace-params = [<custom-params> | <predefined-rgb-params> | <xyz-params>]
custom-params = <dashed-ident> [ <number> | <percentage> ]#
predefined-rgb-params = <predefined-rgb> [ <number> | <percentage> ]{3}
predefined-rgb = srgb | display-p3 | a98-rgb | prophoto-rgb | rec2020
xyz-params = xyz <number>{3}

Within a relative color syntax color() function using <custom-params>, the number and name of the allowed channel keywords are:

• defined by the components descriptor on the corresponding @color-profile, if present; otherwise, no relative color manipulation is valid. They are <percentage>s that correspond to the origin color’s channels after its conversion to the color space of the color profile.

Within a relative color syntax color() function using <predefined-rgb-params>, the allowed channel keywords are:

• r, g, and b are all <percentage>s that correspond to the origin color’s red, green, and blue channels after its conversion to the predefined RGB color space.

Within a relative color syntax color() function using <xyz-params>, the allowed channel keywords are:

• x, y, z are all <number>s that correspond to the origin color’s X, Y and Z channels after its conversion to relative, D50-adapted CIE XYZ color space.

6. Serialization

This section extends CSS Color 4 §4.7 Serializing <color> Values to add serialization of the results of the color-mix(), color-contrast(), and relative color functions.

In this section, the strings used in the specification and the corresponding characters are as follows.

The string "." shall be used as a decimal separator, regardless of locale, and there shall be no thousands separator.

As usual, if the alpha of the result is exactly 1, it is omitted from the serialization; an implicit value of 1 (fully opaque) is the default.

6.1. Serializing color-mix()

The serialization of the result of a color-mix() function is a <color>, as defined in CSS Color 4 §4.7 Serializing <color> Values. The form used depends on the color space specified with "in".

color-mix(in lch, peru 40%, palegoldenrod)

color-mix(in srgb, peru 40%, palegoldenrod)

6.2. Serializing color-contrast()

The serialization of the result of a color-contrast() function is a <color>, as defined in CSS Color 4 §4.7 Serializing <color> Values. The form used is the same as that used to specify the winning color.

color-contrast(wheat vs olive, sienna, maroon)

color-contrast(wheat vs color(prophoto-rgb 0.4 0.4 0.2), color(display-p3 0.45 0.08 0.05))

6.3. Serializing relative color-mix()

The serialization of the result of a relative color function is a <color>, as defined in CSS Color 4 §4.7 Serializing <color> Values. The form used is the same as that used to specify the relative color, but using the absolute form.

lch(from peru calc(l * 0.8) calc(c * 0.7) calc(h + 180)) 

7. Security and Privacy Considerations

No new security or privacy considerations have been reported on this specification.

8. Accessibility Considerations

This specification introduces a new feature to help stylesheet authors write stylesheets which conform to WCAG 2.1 section 1.4.3 Contrast (Minimum).

9. Changes

9.1. Since the Working Draft of 1 June 2021

• Defined serialization of the results of the color-mix, color-contrast, and relative color syntaxes

9.2. Since the FPWD of 10 June 2020

• Added relative color syntax for the color() function
• Clarified that the color-adjuster is not optional
• Clarified that the percentage in color-mix is mandatory
• Moved hue-adjuster back to color-mix whee it belongs
• Added example with different mxing color spaces
• Added examples of percentage normalization in color-mix()
• Explicitly excluded negative percentages in color-mix()
• Percentages in color-mix() summing to less than 100% produce an alpha transparency less than 100%
• Consistently used the term color space rather than colorspace, defined <color-space> token
• Corrected color-contrast grammar
• Added an optional target contrast ratio to color-contrast()
• Corrected adjuster grammar
• Noted that the corner case of percentages summing to zero needs to be handled
• Clarified order of operations in color-mix()
• Updated examples to match current grammar
• Defined how percentages are normalized
• Clarify meaning of 0% and 100% in color-mix()
• Definition of adjusters moved from color-mix() to color-adjust()
• Allow arguments to color-mix() to be in any order
• Mandatory color space for color-mix()
• Allowed the percentage in color-mix() to come before the color
• Added explicit algorithm for color-mix()
• Removed adjusters from color-mix() and simplified the grammar
• Added the "in" keyword to specify the color space used for mixing
• Required color-contrast() list to have at least two items
• Improved explanation of the relative color syntax
• Link to CSS 4 definition of color serialization
• Added separate section for color spaces
• Updated color-adjust example
• Added explanatory diagrams
• Deal with unresolved percentages
• Normalize arguments to color-mix
• Allow percentages for adjusters
• Link fixes
• Updated color-mix grammar, allowing adjusters, add alpha adjuster
• Corrections to some examples
• Updated Security and Privacy section
• added vs keyword to color-contrast
• added xyz adjuster to grammar
• added hue adjuster keywords
• add XYZ color space for mixing
• defined color-adjuster and color space
• allowed mix percent to default to 50%
• added worked examples and diagrams
• corrected minor spelling, syntax and formatting issues

Conformance

Document conventions

Conformance requirements are expressed with a combination of descriptive assertions and RFC 2119 terminology. The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this document are to be interpreted as described in RFC 2119. However, for readability, these words do not appear in all uppercase letters in this specification.

All of the text of this specification is normative except sections explicitly marked as non-normative, examples, and notes. [RFC2119]

Examples in this specification are introduced with the words “for example” or are set apart from the normative text with class="example", like this:

Informative notes begin with the word “Note” and are set apart from the normative text with class="note", like this:

Note, this is an informative note.

Advisements are normative sections styled to evoke special attention and are set apart from other normative text with <strong class="advisement">, like this: UAs MUST provide an accessible alternative.

Tests relating to the content of this specification may be documented in “Tests” blocks like this one. Any such block is non-normative.

Conformance classes

Conformance to this specification is defined for three conformance classes:

A style sheet is conformant to this specification if all of its statements that use syntax defined in this module are valid according to the generic CSS grammar and the individual grammars of each feature defined in this module.

A renderer is conformant to this specification if, in addition to interpreting the style sheet as defined by the appropriate specifications, it supports all the features defined by this specification by parsing them correctly and rendering the document accordingly. However, the inability of a UA to correctly render a document due to limitations of the device does not make the UA non-conformant. (For example, a UA is not required to render color on a monochrome monitor.)

An authoring tool is conformant to this specification if it writes style sheets that are syntactically correct according to the generic CSS grammar and the individual grammars of each feature in this module, and meet all other conformance requirements of style sheets as described in this module.

Partial implementations

So that authors can exploit the forward-compatible parsing rules to assign fallback values, CSS renderers must treat as invalid (and ignore as appropriate) any at-rules, properties, property values, keywords, and other syntactic constructs for which they have no usable level of support. In particular, user agents must not selectively ignore unsupported component values and honor supported values in a single multi-value property declaration: if any value is considered invalid (as unsupported values must be), CSS requires that the entire declaration be ignored.

Implementations of Unstable and Proprietary Features

To avoid clashes with future stable CSS features, the CSSWG recommends following best practices for the implementation of unstable features and proprietary extensions to CSS.

Non-experimental implementations

Once a specification reaches the Candidate Recommendation stage, non-experimental implementations are possible, and implementors should release an unprefixed implementation of any CR-level feature they can demonstrate to be correctly implemented according to spec.

To establish and maintain the interoperability of CSS across implementations, the CSS Working Group requests that non-experimental CSS renderers submit an implementation report (and, if necessary, the testcases used for that implementation report) to the W3C before releasing an unprefixed implementation of any CSS features. Testcases submitted to W3C are subject to review and correction by the CSS Working Group.

Further information on submitting testcases and implementation reports can be found from on the CSS Working Group’s website at http://www.w3.org/Style/CSS/Test/. Questions should be directed to the [email protected] mailing list.

Index

Terms defined by this specification

• a, in §5.2.4
• AA, in §4
• AAA, in §4
• AAA-large, in §4
• AA-large, in §4
• alpha
• c, in §5.2.5
• channel keyword, in §5.2
• color(), in §5.2.6
• color-adjust(), in §5.1
• <color-adjuster>, in §5.1
• color-contrast(), in §4
• color-mix(), in §3
• <color-space>, in §2
• colorspace-params, in §5.2.6
• custom-params, in §5.2.6
• hsl, in §2
• hsl(), in §5.2.2
• <hsl-adjuster>, in §5.1
• <hue-adjuster>, in §3
• hwb, in §2
• hwb(), in §5.2.3
• <hwb-adjuster>, in §5.1
• lab, in §2
• lab(), in §5.2.4
• <lab-adjuster>, in §5.1
• lch, in §2
• lch(), in §5.2.5
• <lch-adjuster>, in §5.1
• origin color, in §5.2
• predefined-rgb, in §5.2.6
• predefined-rgb-params, in §5.2.6
• relative color, in §5.2
• rgb(), in §5.2.1
• s, in §5.2.2
• srgb, in §2
• <srgb-adjuster>, in §5.1
• w, in §5.2.3
• x, in §5.2.6
• xyz, in §2
• <xyz-adjuster>, in §5.1
• xyz-params, in §5.2.6
• y, in §5.2.6
• z, in §5.2.6

Terms defined by reference

• [css-color-3] defines the following terms:
  • <color>
• [css-color-4] defines the following terms:
  • <alpha-value>
  • <hue>
  • @color-profile
  • black
  • components
  • darkolivegreen
  • green
  • white
• [css-values-3] defines the following terms:
  • <angle>
  • <number>
  • <percentage>
• [css-values-4] defines the following terms:
  • <dashed-ident>
  • math function

References

Normative References

Issues Index