Untitled

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>
  <div id="wrapper">
    <header>a</header>
    <nav>
      <ul>
        <li>een</li>
        <li>twee</li>
        <li>drie</li>
      </ul>
    </nav>
    <aside>
    </aside>
    <section>c
    </section>
    <footer>d</footer>
  </div>
</body>
</html>