.arena {
  position: relative;
  height: 300px;
  margin: 1rem 0;
  background: var(--bg-raised);
  border: 2px solid var(--magenta);
  overflow: hidden;
}

.star {
  position: absolute;
  width: 64px;
  height: 64px;
  font-size: 2.5rem;
  line-height: 1;
  color: var(--cyan);
  background: none;
  border: none;
  cursor: pointer;
  text-shadow: 0 0 12px var(--cyan);
  display: none; /* shown while playing */
}