<!DOCTYPE html> <title>@scope - ShadowDOM</title> <link rel="help" href="https://drafts.csswg.org/css-cascade-6/#scope-atrule"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="/resources/declarative-shadow-dom-polyfill.js"></script> <div id=host_plain> <template shadowrootmode=open> <style> @scope (:host) { .a { z-index: 1; } } </style> <div class=a> </div> </template> </div> <script> setup(() => { polyfill_declarative_shadow_dom(document); }); test(() => { let a = host_plain.shadowRoot.querySelector('.a'); assert_equals(getComputedStyle(a).zIndex, '1'); }, '@scope can match :host'); </script> <div id=host_functional> <template shadowrootmode=open> <style> @scope (:host(div)) { .a { z-index: 1; } } /* Should not match: */ @scope (:host(span)) { .a { z-index: 42; } } </style> <div class=a> </div> </template> </div> <script> setup(() => { polyfill_declarative_shadow_dom(document); }); test(() => { let a = host_functional.shadowRoot.querySelector('.a'); assert_equals(getComputedStyle(a).zIndex, '1'); }, '@scope can match :host(...)'); </script>