#grid-chooser {
  width: 120px;
  height: 120px;
  background: lightgray;
  position: absolute;
  padding: 2px;
  display: block;
  z-index: 100;
}

#grid-chooser .row:first-child .square:first-child .inner {
  background: rgba(0,0,0,0.4);
}

#grid-chooser .square:first-child {
  margin-top: 0;
}

#grid-chooser .row {
  height: calc(100%/5);
}
#grid-chooser .square {
  height: 100%;
  width: calc(100%/5);

  display: inline-block;
  margin: -2px 0;
  padding: 1px;
}
#grid-chooser .square:hover .inner, #grid-chooser .square.highlight .inner {
  background: rgba(0,0,0,0.4)
}

#grid-chooser .inner {
  height: 100%;
  width: 100%;
  border-radius: 3px;
  background: rgba(0,0,0,0.2);
}