body
{
    width: 100%;
    height: 100%;
    background-color:lightslategray;
    padding:0;
    display: block;
    clear:both;
    color:whitesmoke;
    margin:0;
    background-image: url(bg.jpg);
    background-size: 100%;
}
div
{
    display: block;
    border: auto;
    margin: auto;
    clear:both;
    float: none;
    position: relative;
    top: 50%;
    font-family: sans-serif;
    font-size: xx-large;
    font-weight: 900;
    text-align: center;
}