[csswg-drafts] [css-overflow] Should `overflow-clip-margin` take percentages? (#5130)

frivoal has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-overflow] Should `overflow-clip-margin` take percentages? ==
When we resolved in #4934 to introduce `overflow-clip-margin`, we did not discuss whether it should take a `<length>` or a `<length-percentage>`.

`margin` takes a `<length-percentage>`, but [the new spec text](https://drafts.csswg.org/css-overflow-3/#overflow-clip-margin) defines `overflow-clip-margin` to take a `<length>`. We didn't discuss that point. On the one hand, analogy with `margin` would suggest `<length-percentage>`. On the other hand, `overflow-clip-margin` is mainly expected to be used to account for things like shadows and outlines, which do not take percentages. I'm leaning towards leaving it as a `<length>`, but not 100% sure, and we didn't discuss.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5130 using your GitHub account