    </p>
    </template>
    <script>
      let gp = document.createElement('green-p').shadowRoot?.children[0];
      test(gp === undefined, 'green-p not registered');

      sb.register();
      gp = document.createElement('green-p').shadowRoot?.lastElementChild;
      test(gp instanceof HTMLParagraphElement, 'el green-p has p shadowRoot');
      test(gp.style.color === 'green', 'green-p has style.color green');
    </script>

    <red-p id="2" sb-mark="a">red</red-p>
    <green-p id="3" sb-mark="b">green<