Implement the @scroll-timeline at-rule and animation-timeline property. See spec https://drafts.csswg.org/scroll-animations-1/ Relevant bugs from other vendors: - Chromium: https://bugs.chromium.org/p/chromium/issues/detail?id=1023424 (Already available, behind a flag, in Chromium 89+) - Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1676780