#grid-board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  max-width: 400px;
  margin: 0 auto 16px;
  padding: 12px;
  border-radius: 14px;
  background: rgba(12, 22, 43, 0.75);
  border: 1px solid var(--line);
  touch-action: none;
}

.tile-cell {
  aspect-ratio: 1;
  border-radius: 10px;
  background: rgba(6, 11, 22, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
}

.tile {
  width: 100%;
  height: 100%;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: clamp(12px, 4vw, 20px);
  font-family: "Consolas", "SF Mono", monospace;
  color: var(--text);
  background: rgba(68, 211, 255, 0.2);
  border: 1px solid rgba(68, 211, 255, 0.35);
}

.tile-v4 { background: rgba(68, 211, 255, 0.28); }
.tile-v8 { background: rgba(96, 165, 250, 0.35); }
.tile-v16 { background: rgba(129, 140, 248, 0.4); color: #fff; }
.tile-v32 { background: rgba(167, 139, 250, 0.45); }
.tile-v64 { background: rgba(192, 132, 252, 0.5); }
.tile-v128,
.tile-v256,
.tile-v512,
.tile-v1024,
.tile-v2048 {
  background: linear-gradient(135deg, #7c3aed, #44d3ff);
  font-size: clamp(10px, 3.5vw, 16px);
}

.game-actions {
  text-align: center;
}