.board-wrap {
  display: flex;
  justify-content: center;
}

.board {
  position: relative;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  width: min(440px, 100%);
  aspect-ratio: 1 / 1;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: color-mix(in srgb, var(--panel) 88%, transparent);
  box-shadow: var(--shadow);
  touch-action: none;
  user-select: none;
}

.tile {
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  background: color-mix(in srgb, var(--muted) 12%, transparent);
  color: #4b5563;
  font-size: clamp(18px, 6vw, 30px);
  font-weight: 800;
  letter-spacing: 0;
  transition: transform 0.12s ease;
}

.tile.is-new {
  animation: tile-pop 0.16s ease-out;
}

.tile.is-merged {
  animation: tile-merge 0.18s ease-out;
}

@keyframes tile-pop {
  from {
    transform: scale(0.7);
    opacity: 0.4;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}

@keyframes tile-merge {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.12);
  }
  100% {
    transform: scale(1);
  }
}

.tile[data-value="2"] { background: #eee4da; }
.tile[data-value="4"] { background: #ede0c8; }
.tile[data-value="8"] { background: #f2b179; color: #ffffff; }
.tile[data-value="16"] { background: #f59563; color: #ffffff; }
.tile[data-value="32"] { background: #f67c5f; color: #ffffff; }
.tile[data-value="64"] { background: #f65e3b; color: #ffffff; }
.tile[data-value="128"] { background: #edcf72; color: #ffffff; }
.tile[data-value="256"] { background: #edcc61; color: #ffffff; }
.tile[data-value="512"] { background: #edc850; color: #ffffff; }
.tile[data-value="1024"] { background: #edc53f; color: #ffffff; }
.tile[data-value="2048"] { background: #edc22e; color: #ffffff; }
.tile[data-value="4096"] { background: #3c3a32; color: #ffffff; }
.tile[data-value="8192"] { background: #2f2d27; color: #ffffff; }

[data-theme="dark"] .tile {
  color: #f4f4f5;
}

[data-theme="dark"] .tile[data-value="2"] { background: #3a3a3f; }
[data-theme="dark"] .tile[data-value="4"] { background: #45454c; }
[data-theme="dark"] .tile[data-value="8"] { background: #8a5a2b; }
[data-theme="dark"] .tile[data-value="16"] { background: #a05f2f; }
[data-theme="dark"] .tile[data-value="32"] { background: #b05a3a; }
[data-theme="dark"] .tile[data-value="64"] { background: #c04a2a; }
[data-theme="dark"] .tile[data-value="128"] { background: #9a8330; }
[data-theme="dark"] .tile[data-value="256"] { background: #a8892c; }
[data-theme="dark"] .tile[data-value="512"] { background: #b09028; }
[data-theme="dark"] .tile[data-value="1024"] { background: #b89524; }
[data-theme="dark"] .tile[data-value="2048"] { background: #c39b1f; }