https://drafts.csswg.org/css-nesting/#cssom-style Add support to manage (insertion, deletion, setSelectorText in nested context) nested rules in a style rule from the CSS Object Model API.
<rdar://problem/107322119>
Pull request: https://github.com/WebKit/WebKit/pull/12121
Committed 262394@main (90d00dc15a7b): <https://commits.webkit.org/262394@main> Reviewed commits have been landed. Closing PR #12121 and removing active labels.
Committed 259548.557@safari-7615-branch (643e62970699): <https://commits.webkit.org/259548.557@safari-7615-branch> Reviewed commits have been landed. Closing PR #526 and removing active labels.