[csswg-drafts] [css-color-5] Should origin colors serialize as their declared value? (#12543)

Gingeh has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-color-5] Should origin colors serialize as their declared value? ==
The specification states:
> The serialization of a the declared value of a color used as the [origin color](https://www.w3.org/TR/css-color-5/#origin-color) inside of another color function as components of a declared value is:
> 1. For [rgb()](https://www.w3.org/TR/css-color-4/#funcdef-rgb), [rgba()](https://www.w3.org/TR/css-color-4/#funcdef-rgba), [hsl()](https://www.w3.org/TR/css-color-4/#funcdef-hsl), [hsla()](https://www.w3.org/TR/css-color-4/#funcdef-hsla)
> - the string identifying the canonical color function, "rgb" for [rgb()](https://www.w3.org/TR/css-color-4/#funcdef-rgb) and [rgba()](https://www.w3.org/TR/css-color-4/#funcdef-rgba), "hsl" for [hsl()](https://www.w3.org/TR/css-color-4/#funcdef-hsl) and [hsla()](https://www.w3.org/TR/css-color-4/#funcdef-hsla), in all-lowercase, followed by "(", followed by a space separated list of the non-alpha components as specified (numbers serializing as numbers, percentages serializing as percentages, angles serializing as canonicalized angles in degrees, calc() serializing in its simplified form) with no clamping applied, followed by " / " and the alpha component as specified (using the same rules as the color components) if an alpha component is present, followed by ")".

But existing implementations (Gecko, Chromium, Webkit) ignore this and serialize origin colors as their declared value.
WPT also expects this non-spec behavior: https://wpt.live/css/css-color/parsing/color-valid-relative-color.html

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/12543 using your GitHub account


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Received on Wednesday, 30 July 2025 03:38:59 UTC