.mask_wrap{
	display: table;
	overflow: hidden;
}
.mask-wrap .mask{
	display: table;
	position: relative;
	margin-bottom: .25em;
	left: -100%;
	overflow: hidden;
}
.mask-wrap .mask-bg{
	display: block;
	position: absolute;
	left: 0;
	top: 0;
	width: 100%;
	height: 100%;
	background: #333;
}