index.html

<!DOCTYPE html>
<html>

<head>
  <meta http-equiv="pragma" content="no-cache" />
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
  <meta name="renderer" content="webkit" />
  <title>mui</title>
  <link rel="stylesheet" href="app.css">
  <style media="screen">
    body{
      font-family: Helvetica Neue For Number,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,PingFang SC,Hiragino Sans GB,Microsoft YaHei,Helvetica Neue,Helvetica,Arial,sans-serif;
    }
    .datepicker {
      margin-bottom: 10px
    }
  </style>
</head>

<body>
  <div id="app"></div>
  <script src="app.js" charset="utf-8"></script>
</body>

</html>