css.types.color.system-color - It's unclear which system color keywords are supported

What type of issue is this?

Missing compatibility data

What information was incorrect, unhelpful, or incomplete?

The page for the <system-color> CSS data type states that system colors (with the exception of Mark, MarkText, and ButtonBorder) are supported across all of the browsers listed in the browser compatibility table. However, the list of system colour keywords has changed over the years, and it's not clear which colors are supported.

I believe that system colours were first introduced in CSS2, deprecated in CSS Color Module Level 3, but then revived, and the list of named colors changed, in CSS Color Module Level 4.

I think that where the current browser compatibility table lists support for "system colors", it's referring to the list of colours defined in CSS2.

Mark, MarkText, ButtonBorder were added in CSS Color Module Level 4, and they are listed separately in the browser compatibility table. However, other colors introduced in CSS Color Module Level 4, like Canvas and CanvasText, and AccentColor and AccentColorText, aren't listed separately.

Another aspect to consider is that CSS Color Module Level 4 states that the older list of CSS2 system color keywords is deprecated, and that browsers should map these values to the newer, not deprecated colors (see https://www.w3.org/TR/css-color-4/#deprecated-system-colors). However, it seems that browser support for this change is very limited, and the spec states that this "feature is at-risk".

What browsers does this problem apply to, if applicable?

No response

What did you expect to see?

Browser compatibility data for newer CSS Color Module Level 4 system color keywords. Given that the content of the page lists these newer colours, and separately lists the older colors under a "Deprecated system color keywords" section, I'd expected to see separate compatibility data for each.

Did you test this? If so, how?

No.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

No response

Do you have anything more you want to share?

Note that there's a separate issue refering to AccentColor: https://github.com/mdn/browser-compat-data/issues/21006.

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/system-color

MDN metadata

MDN page report details

• Query: css.types.color.system-color
• Report started: 2023-10-27T15:25:52.510Z

Start with the BCD query css.types.color.system-color and the linked MDN system-color page, then compare its compatibility claims with the CSS Color 4 system-color definitions and the deprecated CSS2 list. Determine which newer keywords need separate browser data, and consider the related AccentColor issue. Done means the compatibility data clearly distinguishes the relevant keyword sets and matches the specifications.