body {
	margin:0px;
	background:#D8D9DA;
	width:100%; 
	height:100%;
}
#mainDiv {
	position:absolute;
	left:50%;
	top:50%;
	width:860px;
	height:674px;
	margin-left:-430px;
	margin-top:-337px;
	z-index:1;
}