
</head>
<body>

<nav class="navbar navbar-dark bg-dark">
    <div class="container-fluid">
        <a class="navbar-brand" href="#">
            Tuyucheng &ndash; Content Security Policy
        </a>
    </div>
</nav>
<br/>
<div class="container">

    <div class="row  justify-content-center">
        <div class="col-6">
            <div class="alert alert-warning" role="alert">
                Session time out. Please login.
            </div>
        </div>
    </div>
    <div class="row justify-content-