.parent-block{
	width: 100%;
	height: 100%;
	top: 0;
}
.parent-block > div{
	width: 100%;
	height: 100%;
}
.parent-block .block{
	width: 100%;
	height: 100%;
	position: absolute;
	top: 0;
	background: gray;
	opacity: .5;
	z-index: 10000;
}