css/css-cascade/scope-shadow-sharing.html

<!DOCTYPE html>
<html class="test-wait">
<title>@scope - Shadow DOM with shared style data</title>
<link rel="help" href="https://drafts.csswg.org/css-cascade-6/#scoped-styles">
<link rel="match" href="scope-shadow-sharing-ref.html">
<div id="host1">
</div>
<div id="host2">
</div>
<template id="t">
  <style>
    div {
      padding: 3px;
      border: 1px solid;
      background: white;
    }

    @scope {
      div {
        background: red;
      }
    }

    @scope (.explicit-scope) {
      div {
        background: green;
      }
    }
  </style>
  <div>
    <style>
      @scope {
        div {
          background: blue;
        }
      }
    </style>
    <div></div>
  </div>
  <div class="explicit-scope">
    <div></div>
  </div>
</template>
<script>
const hosts = [host1, host2];
for (const host of hosts) {
  const shadowRoot = host.attachShadow({ mode: "open" });
  shadowRoot.append(t.content.cloneNode(true));
}
document.documentElement.className = '';
</script>
</html>