用CSS创建一个三角形

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      div {
         0;
        height: 0;
        border-top: 40px solid transparent;
        border-left: 40px solid transparent;
        border-right: 40px solid transparent;
        border-bottom: 40px solid #ff0000;
      }
    </style>
  </head>
  <body>
    <div></div>
  </body>
</html>
原文地址:https://www.cnblogs.com/doudou-song/p/13700354.html