Hi webkit-dev, This is a request for WebKit's position on CSS tree-scoped names and references for @font-face, @keyframes, @counter-style and other name-defining at-rules. Spec: https://drafts.csswg.org/css-scoping/#shadow-names Explainer: https://drafts.csswg.org/css-scoping/#example-f1503361 https://drafts.csswg.org/css-scoping/#example-ee72cb37 Existing WebKit bug: I'm not aware of any WebKit bug for exactly the same issue. Please let me know if I missed any. There are some related bugs as listed below: https://bugs.webkit.org/show_bug.cgi?id=72461 https://bugs.webkit.org/show_bug.cgi?id=186837 Summary: It has been a long standing issue on how name-defining at-rules should be handled across shadow tree boundaries. The existing behaviors are non-interoperable between browsers, and even inconsistent in the same browser between different rules [1]. Following a recent CSSWG resolution [2], a new and reasonable behavior has been proposed. Chrome is planning to implement this new behavior, starting with the @counter-style rule [3]. [1] https://wiki.csswg.org/spec/css-scoping [2] https://github.com/w3c/csswg-drafts/issues/1995#issuecomment-848941922 [3] https://chromestatus.com/feature/5716198446596096