.app {
  width: min(480px, 100%);
}

.score-bar {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.score-block {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px 14px;
  text-align: center;
  display: grid;
  gap: 2px;
}

.score-label {
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.score-value {
  font-size: 26px;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}

.board-wrap {
  position: relative;
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--surface);
}

.board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  padding: 6px;
  aspect-ratio: 1;
}

.cell {
  background: rgba(255, 255, 255, 0.04);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 28px;
  color: var(--text);
  transition: all 0.1s ease;
  position: relative;
}

.cell[data-value="2"]    { background: #eee4da; color: #776e65; }
.cell[data-value="4"]    { background: #ede0c8; color: #776e65; }
.cell[data-value="8"]    { background: #f2b179; color: #f9f6f2; }
.cell[data-value="16"]   { background: #f59563; color: #f9f6f2; }
.cell[data-value="32"]   { background: #f67c5f; color: #f9f6f2; }
.cell[data-value="64"]   { background: #f65e3b; color: #f9f6f2; }
.cell[data-value="128"]  { background: #edcf72; color: #f9f6f2; font-size: 24px; }
.cell[data-value="256"]  { background: #edcc61; color: #f9f6f2; font-size: 24px; }
.cell[data-value="512"]  { background: #edc850; color: #f9f6f2; font-size: 24px; }
.cell[data-value="1024"] { background: #edc53f; color: #f9f6f2; font-size: 20px; }
.cell[data-value="2048"] { background: #edc22e; color: #f9f6f2; font-size: 20px; }

.cell.pop {
  animation: pop 0.2s ease;
}

@keyframes pop {
  0% { transform: scale(1); }
  50% { transform: scale(1.1); }
  100% { transform: scale(1); }
}

.overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  animation: fadeIn 0.25s ease;
}

.overlay-content {
  text-align: center;
}

.overlay-content h2 {
  margin: 0 0 12px;
  font-size: 32px;
  color: var(--danger);
}

.win-title {
  color: #edc22e !important;
}

.go-score {
  font-size: 16px;
  color: var(--muted);
  margin: 0 0 20px;
}

#finalScore, #winScore {
  color: var(--accent);
  font-weight: 700;
}

.overlay-content .btn + .btn {
  margin-left: 8px;
}

.controls-row {
  display: flex;
  gap: 8px;
  justify-content: center;
}

.tip {
  margin: 0;
  text-align: center;
  font-size: 12px;
  color: var(--muted);
}

.hidden {
  display: none !important;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}