html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    background-color: #111;
    display: table;
    font-family: arial;
}

h1 {
    color: #DDD;
}

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