.main {
	height: 100%;
	width: 100%;
	position: absolute;
	left: 0px;
	top: 0px;
	right: 0px;
	bottom: 0px;
	margin-left:auto;
	margin-right:auto;
}
.content {
	position:absolute;
	top:50%;
	left:50%;
	width:1000px;
	height:700px;
	margin-left:-500px;
	margin-top:-350px;
}