div#inventory {
  cursor: default;
  user-select: none;

  padding-top: 0.2em;

  h4 {
    margin: 1em 0;
  }
}
div#inventory ul {
  list-style-type: none;

  padding-left: 0;
  margin: auto;

  position: relative;
}
div#inventory ul li.item-slot {
  display: inline-block;
  position: relative;

  vertical-align: top;

  width: 68px;
  height: 75px;
  font-size: 0.90em;

  border: 1px outset lightgray;
  border-radius: 3px;

  float: left;

  background-color: #ECEFF1;

  padding: 0.3rem 0.15rem;

  &.selected {
    background-color: white;
  }

  .item-slot-number {
    position: absolute;
    right: 3px;
    top: 3px;

    color: #9E9E9E;
  }
}
div#inventory li.item-slot div.icon {
  position: relative;

  img {
    width: 100%;

    margin: auto;
  }
}

.item-slot .item div.item-count {
  position: absolute;
  bottom: 0;
  right: 2px;

  background-color: #E0F7FA;
  font-size: 0.8em;
  padding: 0.15em;
  border: 1px solid #006064;
  border-radius: 3px;
}

div#inventory {
  cursor: default;
  user-select: none;

  padding-top: 0.2em;

  h4 {
    margin: 1em 0;
  }
}
div#inventory ul {
  list-style-type: none;

  padding-left: 0;
  margin: auto;

  position: relative;
}
div#inventory ul li.item-slot {
  display: inline-block;
  position: relative;

  vertical-align: top;

  width: 68px;
  height: 75px;
  font-size: 0.90em;

  border: 1px outset lightgray;
  border-radius: 3px;

  float: left;

  background-color: #ECEFF1;

  padding: 0.3rem 0.15rem;

  &.selected {
    background-color: white;
  }

  .item-slot-number {
    position: absolute;
    right: 3px;
    top: 3px;
    z-index: 5;

    color: #9E9E9E;

    @include text-stroke(white);
  }
}
div#inventory li.item-slot div.icon {
  position: relative;

  img {
    width: 100%;

    margin: auto;
  }
}

.item-slot .item div.item-count {
  position: absolute;
  bottom: 0;
  right: 2px;

  background-color: #E0F7FA;
  font-size: 0.8em;
  padding: 0.15em;
  border: 1px solid #006064;
  border-radius: 3px;
}

Raise z-index and add white stroke to item slots
Raise z-index and add white stroke to item slots
