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
Note that the spec has been updated since originally filing this issue. The gist is that @scroll-timeline at-rule is out of the picture, and has been replaced by many scroll-timeline and view-timeline properties.
The editors have recently asked the spec to move to FPWD, which should happen some time during the next few weeks.
Note this feature will ship in Chrome 115 on July 12