As of Safari Technology Preview 175 (Safari 17.0, WebKit 18617.1.1.2), nested @supports rules are not applied consistent with implementations in Blink and Gecko. In the Codepen linked below, the border color declaration is overridden by the color value specified in the @supports rules and the border-radius rule in the parent selector is completely ignored. https://codepen.io/Membranophonist/pen/rNQPYXe
<rdar://problem/113652033>
Pull request: https://github.com/WebKit/WebKit/pull/21726
Committed 271989@main (0dd51c9b2c6d): <https://commits.webkit.org/271989@main> Reviewed commits have been landed. Closing PR #21726 and removing active labels.
*** Bug 266287 has been marked as a duplicate of this bug. ***