<!DOCTYPE html>
<html class="reftest-wait">
<title>CSS Shadow Parts - Nested Pseudo Classes</title>
<link rel="help" href="https://drafts.csswg.org/css-shadow-parts" >
<link rel="help" href="https://drafts.csswg.org/selectors/#matches">
<link href="https://drafts.csswg.org/selectors/#matches" rel="help">
<link rel="match" href="interaction-with-nested-pseudo-class-ref.html">
<script src="/common/reftest-wait.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<style>
  :root { color: red; }
  ::part(test):is(:focus) { color: green; }
</style>
<div id=host></div>
<script>
  const root = host.attachShadow({mode: 'closed'});
  root.innerHTML = '<button part=test>Should be green on focus</button>';
  const button = root.querySelector('button');
  button.addEventListener('focus', takeScreenshot);
  test_driver.bless('focus button', () => button.focus());
</script>
</html>