Template:Item/style.css

.itembox {
  width: 50px;
  height: 50px;
  background-color: #ddd;
  border-radius: 5px;

  position: relative;
}

.itembox .item-count {
  position: absolute;
  bottom: 0;
  right: 0;
  background-color: rgba(0, 0, 0, 0.5);
  color: #fff;
  padding: 3px;
  line-height: 1;
}