body{
	margin:0px;
		background-color: #f3f3f3;
}
#flash_content {
	position:absolute;
	top: 50%;
	left: 50%;
	width:800px;
	height:550px;
	margin-left: -410px; /*set to a negative number 1/2 of your width*/	
	margin-top: -275px; /*set to a negative number 1/2 of your height*/
	border:1px solid #cccccc;
}