Antti Koivisto

Like Sam suggested I think we should try to land a patch without any new behaviors (Color-mix) first.

I'm concerned about the CSSOM portion of the spec. Adding children to CSSStyleRule would substantially increase implementation complexity of this rarely used corner of CSS. Current WebKit implementation of rule...

Commit log does not make it clear what problem is being fixed. This also needs a test case.

That wouldn't solve the `don't break meannotation` case without something additional because `white-space: nowrap` wouldn't inherit from the pseudo element to the span and it would still break. Also I...

`ruby > :not(rb, rbc, rtc, ruby)` is ok from perf perspective because it is easily eliminated by the ancestor filter in non-ruby subtrees. I think this is true for all...

The current draft has reduced the complexity compared to one I reviewed by not turning CSSStyleRule into a group rule anymore.

WebKit implements this behavior (in https://bugs.webkit.org/show_bug.cgi?id=249305) as it seems obviously correct. I did change the associated WPT (in https://github.com/web-platform-tests/wpt/pull/37941) to allow `default` as it is not a css-wide keyword. While...