hey guys I have a site layout of 1240px fixed.

and I have this css popup that works perfectly

Code:
.black_overlay{
	display: none;
	position: absolute;
	top: 0%;
	left: 0%;
	width: 100%;
	height: 100%;
	background-color: black;
	z-index:1001;
	-moz-opacity: 0.8;
	opacity:.80;
	filter: alpha(opacity=80);
}
 
.white_content {
	display: none;
	position: absolute;
	top: 25%;
	left: 25%;
	width: 50%;
	height: 50%;
	padding: 16px;
	border: 16px solid orange;
	background-color: white;
	z-index:1002;
	overflow: auto;
So the problem is when I click on the popup from a bigger screen resolution lets say (2500X 1700) the popup covers only my layout of 1240 px.
I want the popup to cover all screen if possible.
how can I do that