.long-page{
	height: 2000px;
}

.mask{
	position: fixed;
  top:0;
  left:0;
  width:100%;
  height:100%;
  background:rgba(0,0,0,.5);
  display:none;;
}

.tips{
	width: 300px;
  height: 300px;
  background: #ff0000;
  position: fixed;
  bottom: 0;
  display:none;
}

.tips.active, .mask.active{
	display:block;
}