设置旋转元素的基点位置 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <style>
    #div1 {
      position: relative;
      height: 200px;
      width: 200px;
      margin: 100px;
      padding: 10px;
      border: 1px solid black;
    }

    #div2 {
      padding: 50px;
      position: absolute;
      border: 1px solid black;
      background-color: red;
      transform: rotate(45deg);
      transform-origin: 20% 40%;
      -ms-transform: rotate(45deg);
      /* IE 9 */
      -ms-transform-origin: 20% 40%;
      /* IE 9 */
      -webkit-transform: rotate(45deg);
      /* Safari and Chrome */
      -webkit-transform-origin: 20% 40%;
      /* Safari and Chrome */
    }
  </style>
</head>

<body>

  <div id="div1">
    <div id="div2">HELLO</div>
  </div>

</body>
</html>
        