用css画一个倒三角

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      <meta charset="UTF-8">
      <meta name="viewport" content="width=device-width, initial-scale=1.0">
      <meta http-equiv="X-UA-Compatible" content="ie=edge">
      <title>Document</title>

      <style>
            div{
             width: 0;
             height: 0;
             border-width: 50px;
             border-style: solid;
             border-color:  red  transparent transparent transparent
            }
      </style>

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<body>


      <div></div>


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原文地址：https://www.cnblogs.com/javascript9527/p/11461678.html