Untitled

<html>
<head>
    <title></title>
    <style>
    body{
        background:black;
    }
    div{
        background:white;
        margin:0 auto;
        width:800px;
    }
    </style>
</head>
<body>
    <div class="">
      <h1>This is a reponsive container</h1>
      <p>This container is <span class=""></span> pixels wide when the browser is <span class=""></span> pixels wide. Resize the browser to see it change.</p>
    </div>
</body>
</html>