.hx-board {
  display: grid;
  gap: 3px;
  width: min(360px, 92vw);
  margin: 0 auto;
  touch-action: manipulation;
}
.hx-cell {
  aspect-ratio: 1 / 1;
  border-radius: 50%;
  background: #e2e8f0;
  cursor: pointer;
  transition: background .12s;
}
.hx-cell.r { background: #ef4444; }
.hx-cell.b { background: #3b82f6; }