#overlay {
	width: 100%;
	height: 100%;
	background: red;
	position: absolute;
	left: 0px;
	top: 0px;
	z-index: 1000;
}
	
	#dialog { background: yellow;
		width: 400px;
		height: 300px;
		position: absolute;
		margin: 0px 0px 0px -200px;
		z-index: 2000;
		top: 10%;
		left: 50%;
	}