body, html{
    display:table;
    
}
.container{
    display:table-cell;
    vertical-align:middle;
}
.container .box{
    width:800px;
    height:600px;
    
    margin:0 auto;
    
}

html {
    height: 100%;
    margin: 0;
    background-repeat: repeat-x;
    background-attachment: fixed;
	background-color: #2F2727;
	background: -moz-linear-gradient(top, #1a82f7, #2F2727 );
	background: -webkit-linear-gradient(top, #1a82f7 0%, #2F2727 100%);
	margin-right: auto; 
	margin-left: auto;
}