This works for normal properties using var()
rdar://104080598
Pull request: https://github.com/WebKit/WebKit/pull/8518
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/37875
Committed 258786@main (fee955ee6904): <https://commits.webkit.org/258786@main> Reviewed commits have been landed. Closing PR #8518 and removing active labels.