NEW307238
@scope styles not applied to elements slotted into Shadow DOM 
https://bugs.webkit.org/show_bug.cgi?id=307238
Summary @scope styles not applied to elements slotted into Shadow DOM
Onur Gumus
Reported 2026-02-07 07:09:21 PST
Created attachment 478280 [details] Bug repro html file Elements styled via @scope lose all styles when they are slotted into a Shadow DOM component. The same styles applied via CSS nesting work correctly. See attached safari-scope-shadow-bug.html for a minimal reproduction. Test 1: @scope without Shadow DOM — PASS (styles applied) Test 2: CSS nesting + Shadow DOM — PASS (styles applied) Test 3: @scope + Shadow DOM — FAIL (no styles applied at all) Chrome render all three correctly.
Attachments
Bug repro html file (3.39 KB, text/html)
2026-02-07 07:09 PST, Onur Gumus 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Ahmad Saleem
Comment 1 2026-02-07 14:39:14 PST
*** WebKit ToT (Minibrowser - 307012@main) *** Reproduces and test 3 does not have 'red' *** Firefox Nightly 149 (20260205213633) *** Does not reproduce and show 'red' properly for 'test 3' *** Chrome Canary 146.0.7672.0 (Official Build) canary (arm64) *** Does not reproduce and show 'red' properly for 'test 3'
Radar WebKit Bug Importer
Comment 2 2026-02-14 07:10:13 PST
<rdar://problem/170388953>
Onur Gumus
Comment 3 2026-02-18 07:50:21 PST
Still broken on the latest tech preview 237
Ahmad Saleem
Comment 4 2026-02-18 13:47:09 PST
(In reply to Onur Gumus from comment #3) > Still broken on the latest tech preview 237 It seems to work fine for me on Safari Technology Preview 237 on Tahoe, are you on Sequoia or Sonoma?
Onur Gumus
Comment 5 2026-02-18 19:05:07 PST
I am on MacOS 26.3 with tech preview 237, it is definitely broken. In chrome bottom bar is red (correct) In Safari bottom bar is transparent (incorrect)
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