console 命令行工具 X clear
console
<!DOCTYPE html>
<html lang="en">
 
<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width,initial-scale=1.0,user-scalable=no" />
  <meta content="telephone=no,email=no" name="format-detection" />
  <style type="text/css">
    .ciropp {
      width: 200px;
      height: 100px;
      border-radius: 8px;
      background: #FFF;
      border: 2px solid red;
      position: relative;
    }
 
    .ciropp::after {
      content: '';
      position: absolute;
      top: 100%;
      left: 20%;
      transform: translate(-50%, -50%) rotate(-45deg);
      /*三角形的方向*/
      width: 15px;
      height: 15px;
      background: #FFF;
      border: 1px solid red;
      border-style: none none solid solid
    }
  </style>
</head>
 
<body>
  <div class="ciropp">今天天气真好</div>
 
  <script src="js/jquery-1.9.1.min.js"></script>
</body>
 
</html>