<!DOCTYPE html>
<title>:scope pseudo does not match in shadow root</title>
<link rel="help" href="https://drafts.csswg.org/css-scoping-1/#host-element-in-tree">
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/11188">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="host"></div>
<script>
  test(() => {
    host.attachShadow({mode: 'open'}).innerHTML = `
    <style>
      div {
        background-color: green;
      }
      :s