<!DOCTYPE html> <html> <head> <title>CSS Shadow Parts - Precedence part vs part</title> <meta href="mailto:fergal@chromium.org" rel="author" title="Fergal Daly"> <link href="http://www.google.com/" rel="author" title="Google"> <link href="https://drafts.csswg.org/css-shadow-parts/" rel="help"> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="support/shadow-helper.js"></script> </head> <body> <style>#c-e-outer::part(part-forwarded) { color: green; }</style> <script>installCustomElement("custom-element-inner", "custom-element-inner-template");</script> <template id="custom-element-inner-template"> <style>span { color: blue; }</style> <span id="green_part" part="partp">This text</span> </template> <script>installCustomElement("custom-element-outer", "custom-element-outer-template");</script> <template id="custom-element-outer-template"> <style>#c-e-inner::part(partp) { color: red; }</style> <custom-element-inner id="c-e-inner" exportparts="partp: part-forwarded"></custom-element-inner> </template> The following text should be green: <custom-element-outer id="c-e-outer"></custom-element-outer> <script> "use strict"; const colorGreen = "rgb(0, 128, 0)"; test(function() { const el = getElementByShadowIds(document, ["c-e-outer", "c-e-inner", "green_part"]); assert_equals(window.getComputedStyle(el).color, colorGreen); }, "Style from document overrides style from outer CE"); </script> </body> </html>