使用百分比来设置元素的最大宽度 - 在线编辑器

          <!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <style>
    p {
      max-width: 20%;
      background-color: yellow;
    }
  </style>
</head>
<body>

  <p>This is some text. This is some text. This is some text. This is some text. This is some text. This is some text. This is some text. This is some text. This is some text.</p>

</body>
</html>
        