[csswg-drafts] [css-inline-3] vertical-align: super and font metrics (#5225)

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

== [css-inline-3] vertical-align: super and font metrics ==
We currently encourage UAs to use the parent font's metrics when positioning a superscript or subscript using `vertical-align`, but it doesn't seem like browser implementations, at least, do that. And I'm guessing making such a change would have noticeable Web-compat implications.

Should we introduce additional keywords, like `font-super` / `font-sub` or an additional `use-font` keyword to allow for using font metrics?

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/5225 using your GitHub account