Re: [csswg-drafts] [css-color] Why not just alias deprecated system colors at parse time? (#13459)

The CSS Working Group just discussed `[css-color] Why not just alias deprecated system colors at parse time?`, and agreed to the following:

* `RESOLVED: Clarify that they "compute" to the other value. (But specified value remains as specified.)`
* `ACTION: Also clarify that they're affected by color-scheme.`

<details><summary>The full IRC log of that discussion</summary>
&lt;emilio> ChrisL: oriol suggested that since deprecated system colors are supposed to be the same, why not aliasing them?<br>
&lt;emilio> ... there seemed to be general agreement<br>
&lt;lea> emilio: Impl-wise it's possible but I think the reason why they're not parsed aliases to begin with in Gecko is we need them to resolve to different values<br>
&lt;lea> ... not a big deal, we can parse-alias them when parsing web content stylesheets, that's just the historical reason<br>
&lt;lea> ... we want to make a title bar match the system color, there's a few colors to represent an active titlte bar, if we want to un-deprecate them that changes behavior<br>
&lt;alisonmaher> q+<br>
&lt;lea> ... that's the only thing that may make parsed aliases more annoying, you'd write div.style.color = "activeCaption", but then it would not roundtrip<br>
&lt;lea> ... if we want to bring some of these back, we have to change behavior again<br>
&lt;lea> q+<br>
&lt;lea> main q is are there some of these we may want to bring back<br>
&lt;lea> ... but no objections<br>
&lt;emilio> ChrisL: ntim also explained some of the WebKit behavior<br>
&lt;emilio> ... something about using them internally<br>
&lt;emilio> emilio: so same thing as gecko, using them internally?<br>
&lt;emilio> ntim: just existing apps using these<br>
&lt;Rossen> ack fantasai<br>
&lt;emilio> fantasai: support the logic emilio articulated, I'd support more explicit writing in the spec saying that they compute to the same, but specified value should remain as specified<br>
&lt;emilio> ChrisL: we're explicit about it<br>
&lt;emilio> fantasai: it says "same as", not "it computes as"<br>
&lt;emilio> ... we should also clarify color-scheme affects this<br>
&lt;emilio> ChrisL: but it does<br>
&lt;emilio> fantasai: yeah agreed, just not super clear in the spec<br>
&lt;emilio> ... doesn't mention the color-scheme property at all<br>
&lt;Rossen> ack alisonmaher<br>
&lt;emilio> alisonmaher: I think if we do believe we might end up with some changes emilio's point is fair<br>
&lt;emilio> ... re the titlebar the current thing is the accentcolor keyword, it doesn't match the inactive state tho<br>
&lt;ChrisL> q+<br>
&lt;emilio> ... not sure the plan is using the deprecated colors tho<br>
&lt;emilio> emilio: fwiw for native titlebar appearance you do need the (windows) active system color<br>
&lt;emilio> ... but not a big deal<br>
&lt;Rossen> ack lea<br>
&lt;emilio> lea: I don't think authors expect perfect roundtrip when setting specified values, lots of colors behave like that<br>
&lt;Rossen> ack ChrisL<br>
&lt;fantasai> PROPOSED: Clarify that they "compute" to the other value. (But specified value remains as specified.)<br>
&lt;emilio> ChrisL: I see some arguments both ways but parse aliasing might be a bit annoying<br>
&lt;florian> +1<br>
&lt;fantasai> RESOLVED: Clarify that they "compute" to the other value. (But specified value remains as specified.)<br>
&lt;fantasai> ACTION: Also clarify that they're affected by color-scheme.<br>
</details>


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Received on Tuesday, 31 March 2026 22:15:24 UTC