Property sheet of SVGStyleElement is undefined in Safari Version 10.0 (11602.1.50.0.10). It works properly in Google Chrome Version 53.0.2785.143 (64-bit). More information including minimal example can be found here: https://github.com/cburgmer/rasterizeHTML.js/issues/158
See https://jsfiddle.net/cburgmer/smea222j/1/ for a test case. The developer console in Chrome reports a parsed rule, while Safari fails for both.
I am able to reproduce this bug in Safari 15.5 on macOS 12.4 based on attached JSFiddle from Comment 01, all other browser output parsed rules but Safari show "undefined". Thanks!
Pull request: https://github.com/WebKit/WebKit/pull/2430
Committed 252491@main (737ccae0f467): <https://commits.webkit.org/252491@main> Reviewed commits have been landed. Closing PR #2430 and removing active labels.
<rdar://problem/97058018>