:root {
  color-scheme: dark;
}

* {
  box-sizing: border-box;
  touch-action: manipulation;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100dvh;
  overflow: hidden;
  background: #0a0a0a;
  color: #f5f5f5;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  -webkit-user-select: none;
  overscroll-behavior: none;
}

main {
  height: 100%;
  max-width: 480px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  padding:
    max(60px, env(safe-area-inset-top))
    16px
    max(20px, env(safe-area-inset-bottom));
  gap: 16px;
}

.score-bar {
  display: flex;
  gap: 8px;
  align-items: stretch;
}

.score-box {
  flex: 1;
  background: #161616;
  border: 1px solid #2a2a2a;
  border-radius: 12px;
  padding: 8px 12px;
  text-align: center;
  min-width: 0;
}

.score-label {
  display: block;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #a0a0a0;
}

.score-val,
.best-val {
  display: block;
  font-size: 22px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  color: #f5f5f5;
  margin-top: 2px;
  line-height: 1.1;
}

.new-btn {
  flex: 0 0 auto;
  font: inherit;
  color: #fff;
  background: #4f9eff;
  border: none;
  border-radius: 12px;
  padding: 0 18px;
  min-height: 56px;
  cursor: pointer;
  font-weight: 700;
  font-size: 14px;
  -webkit-tap-highlight-color: transparent;
}

.new-btn:active { background: #3d8ae8; }

.grid-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.grid {
  --gap: 8px;
  width: min(92vw, 440px);
  aspect-ratio: 1;
  background: #1a1a1a;
  border: 1px solid #2a2a2a;
  border-radius: 14px;
  padding: var(--gap);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 1fr);
  gap: var(--gap);
  touch-action: none;
}

.cell {
  background: #2a2a2a;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  font-size: clamp(20px, 7.5vw, 36px);
  color: #f5f5f5;
  letter-spacing: -0.04em;
  transition: background 0.1s ease, color 0.1s ease, transform 0.08s ease;
}

.cell[data-value="2"]    { background: #eee4da; color: #776e65; }
.cell[data-value="4"]    { background: #ede0c8; color: #776e65; }
.cell[data-value="8"]    { background: #f2b179; color: #fff; }
.cell[data-value="16"]   { background: #f59563; color: #fff; }
.cell[data-value="32"]   { background: #f67c5f; color: #fff; }
.cell[data-value="64"]   { background: #f65e3b; color: #fff; }
.cell[data-value="128"]  { background: #edcf72; color: #fff; font-size: clamp(17px, 6.4vw, 30px); }
.cell[data-value="256"]  { background: #edcc61; color: #fff; font-size: clamp(17px, 6.4vw, 30px); }
.cell[data-value="512"]  { background: #edc850; color: #fff; font-size: clamp(17px, 6.4vw, 30px); }
.cell[data-value="1024"] { background: #edc53f; color: #fff; font-size: clamp(14px, 5.2vw, 24px); }
.cell[data-value="2048"] { background: #edc22e; color: #fff; font-size: clamp(14px, 5.2vw, 24px); }
.cell[data-value="4096"],
.cell[data-value="8192"],
.cell[data-value="16384"] { background: #3c3a32; color: #fff; font-size: clamp(13px, 5vw, 22px); }

/* 오버레이 (게임 종료 / 클리어) */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 20;
  padding: 20px;
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}

.overlay[hidden] { display: none; }

.overlay-card {
  background: #161616;
  border: 1px solid #2a2a2a;
  border-radius: 18px;
  padding: 24px 22px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: center;
  text-align: center;
  min-width: 240px;
  max-width: 320px;
  width: 100%;
}

.overlay-card h2 {
  margin: 0;
  font-size: 22px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.overlay-score {
  margin: 0;
  font-size: 56px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.04em;
  line-height: 1;
}

.overlay-card button {
  font: inherit;
  color: #fff;
  background: rgba(255, 255, 255, 0.10);
  border: 1px solid rgba(255, 255, 255, 0.22);
  border-radius: 999px;
  padding: 12px 20px;
  min-height: 44px;
  cursor: pointer;
  font-weight: 600;
  font-size: 14px;
  width: 100%;
  -webkit-tap-highlight-color: transparent;
}

.overlay-card button:active {
  background: rgba(255, 255, 255, 0.18);
}

.overlay-card .save-btn {
  background: #4f9eff;
  border-color: #4f9eff;
}

.overlay-card .save-btn:active {
  background: #3d8ae8;
}

/* 좌상단 ← 홈, 우상단 🏆 명예의 전당 */
.home-link,
.hof-link {
  position: fixed;
  top: max(12px, env(safe-area-inset-top));
  z-index: 10;
  width: 40px;
  height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.35);
  color: #fff;
  text-decoration: none;
  font-size: 20px;
  font-weight: 600;
  line-height: 1;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  transition: background 0.15s ease;
  border: none;
  cursor: pointer;
  font-family: inherit;
}

.home-link { left:  max(12px, env(safe-area-inset-left)); }
.hof-link  { right: max(12px, env(safe-area-inset-right)); }

@media (hover: hover) {
  .home-link:hover,
  .hof-link:hover {
    background: rgba(0, 0, 0, 0.55);
  }
}