
  }
</style>

<body>
  <div id="top">
    <span>顶部</span>
  </div>
  <div id="middle">
    <div id="left">
      <span>左侧</span>
    </div>
    <div id="center">
      <span>中间</span>
    </div>
    <div id="right">
      <span>右侧</span>
    </div>
  </div>
  <div id="bottom">
    <span>底部</span>
  </div>
</body>

</html>