css: затухание блока градиент

.fading{
	max-height:100px;
	overflow:hidden;
	margin-top:-20px;
}
.fading:before{
	content:"";
	display:block;
	height:20px;
	position:relative;
	top:80px;
	background-image:linear-gradient(to bottom,rgba(255,255,255,0),#ffffff 75%);
}