[csswg-drafts] [css-color-adjust-1] Nits in recent rework of color scheme concepts (#13917)

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

== [css-color-adjust-1] Nits in recent rework of color scheme concepts ==
#13857 reworked the color scheme concepts and the algorithm to determine a used color scheme. I am sorry to do a review here rather than before merging this PR. I had not seen it. There seem to be some oversights.

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https://drafts.csswg.org/css-color-adjust-1/#color-scheme-page

  > Note: In HTML, the `color-scheme` `<meta>` sets the page color scheme.

Doesn't it define the [*page's supported color schemes*](https://html.spec.whatwg.org/multipage/semantics.html#meta-color-scheme:~:text=To%20obtain%20a%20page%27s%20supported%20color%2Dschemes) instead?

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Similarly,  my understanding is that [`normal`](https://drafts.csswg.org/css-color-adjust-1/#valdef-color-scheme-normal) for `color-scheme` sets the element's supported color schemes to the page's supported color schemes.

  > The element color scheme is the same as the page color scheme. (This includes noting whether the color scheme was defaulted.)

And what does `normal` mean in `<meta name="color-scheme">`? A null page's supported color schemes? Should it be specifically handled in the [preliminary steps to determine the page's supporte'd color schemes](https://html.spec.whatwg.org/multipage/semantics.html#meta-color-scheme:~:text=To%20obtain%20a%20page%27s%20supported%20color%2Dschemes)?

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The algo to determine the [used color scheme](https://drafts.csswg.org/css-color-adjust-1/#used-color-scheme) wants *support and preference*:

  > To determine the used color scheme, given a color scheme support `support` and a color scheme preference `preference` [...]

But the call sites provide *preference and support*:

  > The page color scheme is determined by finding the used color scheme, given the preferred color scheme and the page’s supported color schemes (a color scheme support).

  > [...] its element color scheme is determined by finding the used color scheme, given the user’s preferred color scheme and the element’s color scheme support specified by this property.

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The 3rd step to determine the [used color scheme](https://drafts.csswg.org/css-color-adjust-1/#used-color-scheme) is:

  > 3. If `preference`’s color scheme is in `support` and supported by the UA, return that color scheme.

How can the user set a preferred color scheme that is not supported by the UA?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13917 using your GitHub account


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Received on Tuesday, 12 May 2026 19:46:17 UTC