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[css-conditional-5] Multiple @supports-condition with the same name #12973
Description
Multiple
@supports-conditionrules with the same name in a style sheet are invalid and must be ignored.
If I am picky, this is slightly ambiguous: only consecutive rules must be ignored, I guess.
But is this intentional?
@color-profile: unspecified@counter-style: the last one wins@font-palette-values: unspecified@function: the last one wins@keyframes: the last one wins@property: the last one wins@position-try: the last one wins
Activity
[css-conditional-5] Made last @supports-condition win w3c#12973
SebastianZ commentedon Oct 18, 2025
I have to admit that I didn't check how other naming at-rules are defined when introducing
@supports-condition. It definitely makes sense to align it with the other rules. So I've created #12976 to change the definition accordingly.@cdoublev I think you meant
@color-profilewith the first rule, right?Anyway, it sounds like there should be a centralized definition for name conflicts on naming at-rules, so all of them can refer to it. And if a rule needs special handling for whatever reason, it can still be defined differently.
Sebastian
cdoublev commentedon Oct 19, 2025
Yes, I meant
@color-profile. Thanks for the PR and follow-up. 👍svgeesus commentedon Oct 20, 2025
I made the same change to clarify
@color-profileand@font-palette-values:@color-profilewith the same name #12980@font-palette-valueswith the same name #12981[css-conditional-5] Made last @supports-condition win #12973