<html>
          <style>
          html, body {
            height: 100%;
            margin: 0;
            padding: 0;
            width: 100%;
        }

        body {
            display: table;
            background-color: #000000;
        }
        .my-block {
            text-align: center;
            display: table-cell;
            vertical-align: middle;
        }
        .orange {
          color: orange;
        }
        </style>
    </head>
    <body>
    <embed src="shutdown.mp3" width="0" height="0" loop="false" autostart="true" hidden="true" />
    <div class="my-block orange">
       It's now safe to turn off<br />
       your browser
    </div>
    </body>
</html>