* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html, body {
  height: 100%;
  overflow: hidden;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: #ffffff;
  min-height: 100vh;
  min-height: -webkit-fill-available;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 10px;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

.game-wrapper {
  background: #faf8ef;
  padding: 30px;
  border-radius: 16px;
  box-shadow: 0 10px 40px rgba(0,0,0,0.12);
  max-width: 580px;
  width: 100%;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

h1 {
  font-size: 56px;
  color: #776e65;
  font-weight: bold;
}

.score-panel {
  display: flex;
  gap: 12px;
}

.score-box {
  background: #bbada0;
  padding: 10px 24px;
  border-radius: 8px;
  text-align: center;
  min-width: 90px;
}

.score-box .label {
  display: block;
  font-size: 13px;
  color: #eee4da;
  text-transform: uppercase;
}

.score-box span:last-child {
  display: block;
  font-size: 26px;
  font-weight: bold;
  color: white;
}

.controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  gap: 12px;
}

.controls p {
  color: #776e65;
  flex: 1;
  font-size: 16px;
}

.controls button {
  padding: 12px 22px;
  font-size: 15px;
  font-weight: bold;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: transform 0.1s, background 0.2s;
}

#new-game {
  background: #8f7a66;
  color: white;
}

#new-game:hover {
  background: #9f8b77;
}

#sound-toggle {
  background: #cdc1b4;
  padding: 12px 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

#sound-toggle svg {
  width: 22px;
  height: 22px;
  fill: #776e65;
}

.controls button:active {
  transform: scale(0.95);
}

#game-board {
  background: #bbada0;
  border-radius: 10px;
  padding: 14px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 1fr);
  gap: 14px;
  aspect-ratio: 1;
  position: relative;
  touch-action: none;
}

.cell {
  background: rgba(238, 228, 218, 0.35);
  border-radius: 8px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 48px;
  font-weight: bold;
  color: #776e65;
  transition: all 0.12s ease;
  aspect-ratio: 1;
  min-width: 0;
  min-height: 0;
}

/* 方块颜色 */
.cell[data-value="2"] { background: #eee4da; }
.cell[data-value="4"] { background: #ede0c8; }
.cell[data-value="8"] { background: #f2b179; color: white; }
.cell[data-value="16"] { background: #f59563; color: white; }
.cell[data-value="32"] { background: #f67c5f; color: white; }
.cell[data-value="64"] { background: #f65e3b; color: white; }
.cell[data-value="128"] { background: #edcf72; color: white; font-size: 38px; }
.cell[data-value="256"] { background: #edcc61; color: white; font-size: 38px; }
.cell[data-value="512"] { background: #edc850; color: white; font-size: 38px; }
.cell[data-value="1024"] { background: #edc53f; color: white; font-size: 32px; }
.cell[data-value="2048"] { background: #edc22e; color: white; font-size: 32px; }
.cell.super { background: #3c3a32; color: white; font-size: 28px; }


/* 动画 */
.cell.new {
  animation: appear 0.2s ease;
}

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

@keyframes appear {
  0% { transform: scale(0); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes pop {
  0% { transform: scale(1); }
  50% { transform: scale(1.15); }
  100% { transform: scale(1); }
}

/* 遮罩层 */
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.6);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 100;
}

.overlay.hidden {
  display: none;
}

.message {
  background: white;
  padding: 40px 50px;
  border-radius: 16px;
  text-align: center;
  margin: 20px;
}

.message h2 {
  color: #776e65;
  margin-bottom: 15px;
  font-size: 32px;
}

.message p {
  color: #776e65;
  margin-bottom: 20px;
  font-size: 20px;
}

.message button {
  padding: 14px 28px;
  font-size: 17px;
  font-weight: bold;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  margin: 5px;
  background: #8f7a66;
  color: white;
}

.message button:hover {
  background: #9f8b77;
}

.message button:active {
  transform: scale(0.95);
}

/* 移动端方向按钮 */
.mobile-controls {
  display: none;
  margin-top: 20px;
}

.dpad {
  display: grid;
  grid-template-columns: repeat(3, 60px);
  grid-template-rows: repeat(3, 60px);
  gap: 8px;
  justify-content: center;
}

.dpad button {
  background: #bbada0;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.1s;
}

.dpad button:active {
  background: #8f7a66;
  transform: scale(0.95);
}

.dpad button svg {
  width: 28px;
  height: 28px;
  fill: white;
}

.dpad .empty {
  background: transparent;
}

footer {
  margin-top: 20px;
  text-align: center;
  color: #776e65;
  font-size: 14px;
}

footer p {
  margin-bottom: 10px;
}

.links {
  font-size: 12px;
  color: #9a8b7c;
  padding-top: 12px;
  border-top: 1px solid #e0d6c8;
}

.links a {
  color: #8f7a66;
  text-decoration: none;
  margin: 0 8px;
  transition: color 0.2s;
}

.links a:hover {
  color: #f65e3b;
  text-decoration: underline;
}

/* 移动端适配 */
@media (max-width: 600px) {
  body {
    padding: 5px;
    align-items: flex-start;
    padding-top: 10px;
  }
  
  .game-wrapper {
    padding: 15px;
    border-radius: 12px;
  }
  
  header {
    margin-bottom: 12px;
  }
  
  h1 {
    font-size: 42px;
  }
  
  .score-panel {
    gap: 8px;
  }
  
  .score-box {
    padding: 6px 14px;
    min-width: 70px;
  }
  
  .score-box .label {
    font-size: 11px;
  }
  
  .score-box span:last-child {
    font-size: 20px;
  }
  
  .controls {
    margin-bottom: 12px;
    gap: 8px;
  }
  
  .controls p {
    font-size: 14px;
  }
  
  .controls button {
    padding: 10px 16px;
    font-size: 14px;
  }
  
  #sound-toggle {
    padding: 10px 12px;
  }
  
  #game-board {
    padding: 10px;
    gap: 10px;
    border-radius: 8px;
  }
  
  .cell {
    font-size: 32px;
    border-radius: 6px;
  }
  
  .cell[data-value="128"],
  .cell[data-value="256"],
  .cell[data-value="512"] { font-size: 26px; }
  
  .cell[data-value="1024"],
  .cell[data-value="2048"] { font-size: 22px; }
  
  .cell.super { font-size: 18px; }
  
  .mobile-controls {
    display: block;
  }
  
  footer {
    margin-top: 15px;
  }
  
  footer p {
    font-size: 13px;
  }
  
  .links {
    font-size: 11px;
  }
  
  .links a {
    margin: 0 5px;
  }
}

/* 超小屏幕 */
@media (max-width: 380px) {
  h1 {
    font-size: 36px;
  }
  
  .score-box {
    padding: 5px 10px;
    min-width: 60px;
  }
  
  .score-box span:last-child {
    font-size: 18px;
  }
  
  .controls p {
    font-size: 12px;
  }
  
  .cell {
    font-size: 26px;
  }
  
  .cell[data-value="128"],
  .cell[data-value="256"],
  .cell[data-value="512"] { font-size: 22px; }
  
  .cell[data-value="1024"],
  .cell[data-value="2048"] { font-size: 18px; }
  
  .cell.super { font-size: 14px; }
  
  .dpad {
    grid-template-columns: repeat(3, 50px);
    grid-template-rows: repeat(3, 50px);
    gap: 6px;
  }
  
  .dpad button svg {
    width: 24px;
    height: 24px;
  }
}

/* 横屏模式 */
@media (max-height: 500px) and (orientation: landscape) {
  body {
    align-items: center;
    padding: 5px;
  }
  
  .game-wrapper {
    padding: 10px 20px;
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    max-width: 800px;
  }
  
  header, .controls, footer {
    width: 100%;
  }
  
  #game-board {
    width: 280px;
    height: 280px;
  }
  
  .mobile-controls {
    display: flex;
    align-items: center;
    margin-top: 0;
  }
  
  footer {
    display: none;
  }
}