<head>
<template id='shadow-template'>
<style>
:host {
    color: red;
}
</style>
<div></div><h1>Hi from a template!</h1></div>
</template>
</head>
<body class='body-class'>
  <div id='A'> A
    <div id='B'> B
      <div id='C'> C
        <div id='D'> D
          <div id='E'> E
          </div>
        </div>
      </div>
    </div>
  </div>

  <iframe src='./simple-iframe.html' width='400' height='200'></iframe>
  <div id='shadow-host'></div>
</body>