Re: [csswg-drafts] [css-values] Add a way to set longhands to the corresponding expansion of a shorthand value (#8055)

Yes, I think in most cases the information is already known, and otherwise it's probably fine to let UAs come up with a valid answer.

For example, in `-webkit-border-image = 99% / 1px`, WebKit sets `border-image-width` to `1px 1px 1px 1px` with a special bool flag. So:
- This doesn't track the shorthand, but we know it must be `-webkit-border-image` because there is no other way to set that flag
- This doesn't track the original value either, but I think it's probably fine to e.g. serialize as `from-shorthand(-webkit-border-image: 100% / 1px)`, using the initial `border-image-slice: 100%` instead of the specified `99%`. Or as `from-shorthand(-webkit-border-image: none / 1px)`.

Or otherwise, if we want this to always track the original value, it also seems fine because it's only extra storage in corner cases.

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Received on Wednesday, 11 February 2026 21:41:15 UTC