.item{
  position: relative;
  .top{
    position: absolute;
    top: 0;
    left: 0;
  }
  .bottom{
    position: absolute;
    bottom: 0;
    left: 0;
  }
  .center{
    position: absolute;
    top:50%;
  }
}
.item-overlay{
  display: none;
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  &.active,
  .item:hover & {
    display: block;
  }
}