.slots {
  display: flex;
  justify-content: center;
}

.slot {
  width: 5em;
  height: 5em;
}

.board {
  display: inline-grid;
  background: grey;
  border: 0.5em solid grey;
}

.box {
  width: 5em;
  height: 5em;
  background: white;
  border: 0.5em solid grey;
  border-radius: 50%;
}

.active {
  border: 0.5em solid white;
  border-radius: 50%;
}

.button-holder {
  margin: 20px;
  font-size: large;
}