[css-color-4] Add new set of CSS system colors (addresses #3804)

[melanierichards]

Preserves language around system colors from css-color-3; moves undeprecated values from the appendix, leaving behind those which are still deprecated.

[dbaron]

As I mentioned above, I think it would likely be better if something in this section included the deprecated system colors in the <system-color> term so that other pieces of spec wouldn't miss half of them.

[melanierichards]

Besides removing the definition of <deprecated-system-color>, would you mind clarifying what you'd like changed here? Move the deprecated list out of the appendix and into this section (though of course still noting they are deprecated)?

[svgeesus]

@dbaron it looks like this PR is awaiting your clarification of what changes you requested.

[AmeliaBR]

Additional comments:

The security & privacy section needs updating, as we are re-introducing some of the fingerprinting potential of system colors. The introductory section on system colors should probably also explicitly call out this risk.

It would be helpful if new paragraph text could be re-structured to use semantic line breaks.

Also, Melanie, you might need to add yourself to the acknowledgements section!

[melanierichards]

@dbaron @AmeliaBR one thing I wanted to ask after I take the PR out of draft mode was whether it makes sense to have this new section on system colors as its own section of the spec, or if it would make more sense as a subsection under named colors. Do you all have thoughts/opinions on that?

[AmeliaBR]

whether it makes sense to have this new section on system colors as its own section of the spec, or if it would make more sense as a subsection under named colors.

A subsection makes sense. Or maybe the top-level section should be renamed "Color keywords", and then have four subsections below it:

• named colors
• system colors
• transparent
• currentcolor

[melanierichards]

Commit has been updated to include the following changes:

• Moved system colors section under "named colors" section
• Addressed inline feedback, with the exception of clarification on how folks want deprecated system colors integrated into the definition (if other changes made don't suffice)
• Updated language in security & privacy, and referenced from system colors section
• Moved from length-based line breaks to semantic line breaks

[AmeliaBR]

Thanks for the fast updates, Melanie!

On security & privacy, the issue is not just about spoofing, it's also about fingerprinting. See also #3873.

[melanierichards]

@AmeliaBR The security & privacy section of the spec already has a mention for the fingerprinting risk, do we feel it needs more detail? Seems like #3873 might be out of scope for this particular PR, or at least we might need to discuss first as a group?

@Crissov @svgeesus was your upvote on Amelia's comment in favor of renaming the "Named colors" section to "Color keywords"? For now I had just moved system colors within the "Named colors" section.

Thanks all for the feedback!

[AmeliaBR]

I think your current text re security & privacy is accurate. Any discussion of stricter requirements on UAs can happen in the other issue.

[Crissov]

Iʼm I in the favor of renaming the section and adding sub-headings as suggested.

[svgeesus]

@svgeesus was your upvote on Amelia's comment in favor of renaming the "Named colors" section to "Color keywords"?

Yes, it was.

[melanierichards]

Just renamed "Named colors" section => "Color keywords" as requested (and sheepishly added myself to acknowledgements per @AmeliaBR's comment).

Apologies for the intermittent delay on these last changes!