body {
    background-color: black;
    }

p {
    display: table-cell;
    vertical-align: middle;
    text-align: center;
    }

div.container {
    display: table;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    }

img.displayed {
    display: block;
    margin: 1em auto;
    }

div#audio {
  visibility: hidden;
}