:root {
  --bg-main: #0f141c;
  --bg-card: rgba(26, 33, 46, 0.85);
  --bg-card-border: rgba(255, 255, 255, 0.08);
  --bg-board: #bbada0;
  --bg-cell: rgba(238, 228, 218, 0.35);

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-dark: #776e65;
  --text-light: #f9f6f2;

  --accent-gold: #f59e0b;
  --accent-blue: #3b82f6;
  --accent-cyan: #06b6d4;
  --accent-green: #10b981;
  --accent-purple: #8b5cf6;

  --board-padding: 12px;
  --grid-gap: 12px;
  --cell-size: 96px;
  --board-radius: 12px;
  --tile-radius: 8px;

  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  user-select: none;
  -webkit-user-select: none;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-main);
  background-image: 
    radial-gradient(at 0% 0%, rgba(59, 130, 246, 0.12) 0px, transparent 50%),
    radial-gradient(at 100% 100%, rgba(245, 158, 11, 0.08) 0px, transparent 50%);
  color: var(--text-primary);
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  padding-top: max(20px, env(safe-area-inset-top));
  padding-bottom: max(20px, env(safe-area-inset-bottom));
  padding-left: max(16px, env(safe-area-inset-left));
  padding-right: max(16px, env(safe-area-inset-right));
  overflow-x: hidden;
  -webkit-tap-highlight-color: transparent;
}

.app-container {
  width: 100%;
  max-width: 960px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* Header */
.game-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.logo {
  font-size: 3.2rem;
  font-weight: 800;
  letter-spacing: -1px;
  background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 50%, #ea580c 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
}

.badge {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  background: rgba(59, 130, 246, 0.18);
  border: 1px solid rgba(59, 130, 246, 0.35);
  color: #60a5fa;
  padding: 4px 8px;
  border-radius: 6px;
}

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

.score-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(12px);
  padding: 8px 18px;
  border-radius: 10px;
  min-width: 90px;
  text-align: center;
  position: relative;
}

.score-label {
  display: block;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.8px;
  color: var(--text-secondary);
}

.score-value {
  display: block;
  font-size: 1.4rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: #fff;
}

.score-add {
  position: absolute;
  right: 12px;
  top: 10px;
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: 1rem;
  color: #fbbf24;
  opacity: 0;
  pointer-events: none;
}

.score-add.animate {
  animation: floatUp 600ms ease-out forwards;
}

@keyframes floatUp {
  0% {
    opacity: 1;
    transform: translateY(0);
  }
  100% {
    opacity: 0;
    transform: translateY(-24px);
  }
}

/* Layout */
.game-layout {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 28px;
  align-items: start;
}

/* Game Section */
.game-section {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.board-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: calc(var(--cell-size) * 4 + var(--grid-gap) * 3 + var(--board-padding) * 2);
}

.subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.subtitle strong {
  color: #fbbf24;
}

/* Board Container */
.board-container {
  position: relative;
  width: calc(var(--cell-size) * 4 + var(--grid-gap) * 3 + var(--board-padding) * 2);
  height: calc(var(--cell-size) * 4 + var(--grid-gap) * 3 + var(--board-padding) * 2);
  background-color: var(--bg-board);
  border-radius: var(--board-radius);
  padding: var(--board-padding);
  box-shadow: 0 16px 36px rgba(0, 0, 0, 0.45), inset 0 2px 4px rgba(255, 255, 255, 0.1);
  touch-action: none;
  overscroll-behavior: contain;
  margin: 0 auto;
}

.grid-background {
  display: grid;
  grid-template-columns: repeat(4, var(--cell-size));
  grid-template-rows: repeat(4, var(--cell-size));
  gap: var(--grid-gap);
  width: 100%;
  height: 100%;
}

.grid-cell {
  background: var(--bg-cell);
  border-radius: var(--tile-radius);
  width: var(--cell-size);
  height: var(--cell-size);
}

/* Tile Layer */
.tile-container {
  position: absolute;
  top: var(--board-padding);
  left: var(--board-padding);
  right: var(--board-padding);
  bottom: var(--board-padding);
  pointer-events: none;
}

.tile {
  position: absolute;
  width: var(--cell-size);
  height: var(--cell-size);
  border-radius: var(--tile-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: calc(var(--cell-size) * 0.44);
  font-weight: 800;
  font-family: var(--font-sans);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
  transform: translate3d(
    calc(var(--x) * (var(--cell-size) + var(--grid-gap))),
    calc(var(--y) * (var(--cell-size) + var(--grid-gap))),
    0
  );
  transition: transform var(--tile-transition, 100ms) cubic-bezier(0.2, 0.9, 0.3, 1);
  will-change: transform;
}

.tile.tile-new {
  animation: popIn 180ms ease-out forwards;
}

.tile.tile-merged {
  animation: mergeBounce 200ms cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
  z-index: 10;
}

@keyframes popIn {
  0% {
    transform: translate3d(
      calc(var(--x) * (var(--cell-size) + var(--grid-gap))),
      calc(var(--y) * (var(--cell-size) + var(--grid-gap))),
      0
    ) scale(0);
    opacity: 0;
  }
  100% {
    transform: translate3d(
      calc(var(--x) * (var(--cell-size) + var(--grid-gap))),
      calc(var(--y) * (var(--cell-size) + var(--grid-gap))),
      0
    ) scale(1);
    opacity: 1;
  }
}

@keyframes mergeBounce {
  0% {
    transform: translate3d(
      calc(var(--x) * (var(--cell-size) + var(--grid-gap))),
      calc(var(--y) * (var(--cell-size) + var(--grid-gap))),
      0
    ) scale(1);
  }
  50% {
    transform: translate3d(
      calc(var(--x) * (var(--cell-size) + var(--grid-gap))),
      calc(var(--y) * (var(--cell-size) + var(--grid-gap))),
      0
    ) scale(1.18);
  }
  100% {
    transform: translate3d(
      calc(var(--x) * (var(--cell-size) + var(--grid-gap))),
      calc(var(--y) * (var(--cell-size) + var(--grid-gap))),
      0
    ) scale(1);
  }
}

/* Tile Colors & Typographies */
.tile-2 { background: #eee4da; color: var(--text-dark); }
.tile-4 { background: #ede0c8; color: var(--text-dark); }
.tile-8 { background: #f2b179; color: var(--text-light); }
.tile-16 { background: #f59563; color: var(--text-light); }
.tile-32 { background: #f67c5f; color: var(--text-light); }
.tile-64 { background: #f65e3b; color: var(--text-light); }
.tile-128 {
  background: #edcf72;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.38);
  box-shadow: 0 0 15px rgba(243, 215, 116, 0.4);
}
.tile-256 {
  background: #edcc61;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.38);
  box-shadow: 0 0 20px rgba(243, 215, 116, 0.5);
}
.tile-512 {
  background: #edc850;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.38);
  box-shadow: 0 0 25px rgba(243, 215, 116, 0.6);
}
.tile-1024 {
  background: #edc53f;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.31);
  box-shadow: 0 0 30px rgba(243, 215, 116, 0.7);
}
.tile-2048 {
  background: #edc22e;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.31);
  box-shadow: 0 0 35px rgba(237, 194, 46, 0.9), inset 0 0 8px rgba(255, 255, 255, 0.6);
}
.tile-4096 {
  background: #6a5acd;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.31);
  box-shadow: 0 0 35px rgba(106, 90, 205, 0.8);
}
.tile-8192 {
  background: #483d8b;
  color: var(--text-light);
  font-size: calc(var(--cell-size) * 0.31);
  box-shadow: 0 0 35px rgba(72, 61, 139, 0.9);
}
.tile-16384 {
  background: #1e1b4b;
  color: #38bdf8;
  font-size: calc(var(--cell-size) * 0.25);
  box-shadow: 0 0 40px rgba(56, 189, 248, 0.9);
}
.tile-super {
  background: #0f172a;
  color: #ec4899;
  font-size: calc(var(--cell-size) * 0.23);
  box-shadow: 0 0 40px rgba(236, 72, 153, 0.9);
}

/* Overlays */
.game-message {
  position: absolute;
  inset: 0;
  background: rgba(15, 20, 28, 0.88);
  backdrop-filter: blur(8px);
  border-radius: var(--board-radius);
  display: flex;
  justify-content: center;
  align-items: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 250ms ease;
  z-index: 50;
}

.game-message.active {
  opacity: 1;
  pointer-events: auto;
}

.message-content {
  text-align: center;
  padding: 24px;
}

.message-content h2 {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #fff, #94a3b8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.message-content p {
  color: var(--text-secondary);
  margin-bottom: 20px;
  font-size: 1rem;
}

.message-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
}

.manual-hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
  max-width: calc(var(--cell-size) * 4 + var(--grid-gap) * 3 + var(--board-padding) * 2);
}

/* Sidebar Sections */
.sidebar-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: 100%;
  max-width: 420px;
}

.panel-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  backdrop-filter: blur(16px);
  border-radius: 14px;
  padding: 18px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.3);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.card-header h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

/* Status Indicator */
.status-indicator {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.05);
  padding: 4px 8px;
  border-radius: 20px;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--text-muted);
}

.status-indicator.running .status-dot {
  background-color: var(--accent-green);
  box-shadow: 0 0 8px var(--accent-green);
  animation: pulse 1.5s infinite;
}

.status-indicator.running {
  color: #34d399;
}

@keyframes pulse {
  0% { transform: scale(0.95); opacity: 0.7; }
  50% { transform: scale(1.2); opacity: 1; }
  100% { transform: scale(0.95); opacity: 0.7; }
}

.mono-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent-cyan);
  background: rgba(6, 182, 212, 0.12);
  border: 1px solid rgba(6, 182, 212, 0.25);
  padding: 3px 8px;
  border-radius: 6px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: all 150ms ease;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-primary);
  padding: 8px 14px;
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.14);
}

.btn-primary {
  background: linear-gradient(135deg, #3b82f6, #2563eb);
  color: white;
  padding: 10px 20px;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
}

.ai-button-group {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  margin-bottom: 16px;
}

.btn-ai-run {
  background: linear-gradient(135deg, #10b981, #059669);
  color: #fff;
  padding: 12px 18px;
  font-size: 1rem;
  box-shadow: 0 4px 16px rgba(16, 185, 129, 0.35);
}

.btn-ai-run:hover {
  filter: brightness(1.1);
}

.btn-ai-run.running {
  background: linear-gradient(135deg, #ef4444, #dc2626);
  box-shadow: 0 4px 16px rgba(239, 68, 68, 0.35);
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--bg-card-border);
  color: var(--text-primary);
  padding: 12px 18px;
}

.btn-outline:hover {
  background: rgba(255, 255, 255, 0.08);
}

/* Speed Controls */
.speed-control-box {
  display: flex;
  flex-direction: column;
  gap: 8px;
  background: rgba(0, 0, 0, 0.2);
  padding: 12px;
  border-radius: 10px;
}

.speed-label-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.speed-value-display {
  font-family: var(--font-mono);
  font-weight: 600;
  color: #fbbf24;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #fbbf24;
  cursor: pointer;
  box-shadow: 0 0 8px rgba(251, 191, 36, 0.6);
  transition: transform 100ms ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.speed-presets {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  margin-top: 4px;
}

.preset-btn {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--bg-card-border);
  color: var(--text-secondary);
  padding: 6px 4px;
  border-radius: 6px;
  font-size: 0.7rem;
  font-weight: 600;
  text-align: center;
  white-space: nowrap;
  cursor: pointer;
  transition: all 120ms ease;
}

.preset-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
}

.preset-btn.active {
  background: rgba(59, 130, 246, 0.2);
  border-color: rgba(59, 130, 246, 0.4);
  color: #60a5fa;
}

.preset-ultra {
  color: #fb7185;
  border-color: rgba(244, 63, 94, 0.35);
}

.preset-ultra:hover {
  background: rgba(244, 63, 94, 0.15);
  color: #fda4af;
}

.preset-ultra.active {
  background: linear-gradient(135deg, rgba(244, 63, 94, 0.3), rgba(225, 29, 72, 0.45));
  border-color: #f43f5e;
  color: #fff;
  box-shadow: 0 0 10px rgba(244, 63, 94, 0.4);
}

/* Telemetry Grid */
.telemetry-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-bottom: 16px;
}

.telemetry-stat {
  background: rgba(0, 0, 0, 0.25);
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.stat-label {
  display: block;
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.stat-value {
  display: block;
  font-size: 1.1rem;
  font-family: var(--font-mono);
  font-weight: 600;
  color: #fff;
}

.highlight-move {
  color: #38bdf8;
}

.highlight-mps {
  color: #10b981;
  text-shadow: 0 0 10px rgba(16, 185, 129, 0.45);
}

.mps-stat-card {
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.25);
}

.telemetry-stat.full-width {
  grid-column: span 2;
}

/* Heuristic Breakdown Bars */
.heuristic-breakdown {
  display: flex;
  flex-direction: column;
  gap: 12px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 14px;
}

.heuristic-breakdown h4 {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
}

.heuristic-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.heuristic-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.h-val {
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--text-primary);
}

.progress-bar {
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0%;
  border-radius: 3px;
  transition: width 150ms ease-out;
}

.fill-anchor {
  background: linear-gradient(90deg, #f59e0b, #fbbf24);
}

.fill-empty {
  background: linear-gradient(90deg, #10b981, #34d399);
}

.fill-smooth {
  background: linear-gradient(90deg, #6366f1, #818cf8);
}

/* Footer */
.app-footer {
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
  padding-top: 8px;
}

.hidden {
  display: none !important;
}

/* Controls Hint */
.manual-hint {
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-muted);
  padding: 2px 0;
}

.hint-mobile {
  display: none;
}

.tab-label-short {
  display: none;
}

/* Rust WASM Badge & Engine Selector */
.badge-rust-wasm {
  background: rgba(249, 115, 22, 0.18) !important;
  border: 1px solid rgba(249, 115, 22, 0.4) !important;
  color: #fb923c !important;
}

.engine-selector-box {
  background: rgba(0, 0, 0, 0.25);
  border: 1px solid var(--bg-card-border);
  padding: 10px 12px;
  border-radius: 10px;
  margin-bottom: 14px;
}

.engine-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.engine-label {
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--text-muted);
  letter-spacing: 0.5px;
}

.engine-speed-note {
  font-size: 0.72rem;
  font-weight: 600;
  color: #38bdf8;
  font-family: var(--font-mono);
}

.engine-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
  background: rgba(15, 23, 42, 0.6);
  padding: 3px;
  border-radius: 8px;
}

.badge-rust-wasm {
  background: rgba(249, 115, 22, 0.18) !important;
  border-color: rgba(249, 115, 22, 0.4) !important;
  color: #fb923c !important;
}

.badge-cpp-wasm {
  background: rgba(59, 130, 246, 0.18) !important;
  border-color: rgba(59, 130, 246, 0.4) !important;
  color: #60a5fa !important;
}

.badge-js {
  background: rgba(234, 179, 8, 0.18) !important;
  border-color: rgba(234, 179, 8, 0.4) !important;
  color: #facc15 !important;
}

.engine-tab {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.76rem;
  font-weight: 600;
  padding: 6px 6px;
  border-radius: 6px;
  cursor: pointer;
  transition: all 150ms ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  white-space: nowrap;
}

.engine-tab:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.05);
}

.engine-tab.active {
  background: rgba(59, 130, 246, 0.25);
  border-color: rgba(59, 130, 246, 0.5);
  color: #93c5fd;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.engine-tab.active .tab-bolt {
  color: #fbbf24;
}

.tab-bolt {
  font-size: 0.9rem;
}

.tab-gear {
  font-size: 0.85rem;
}

.tab-js {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  background: #f7df1e;
  color: #000;
  padding: 1px 3px;
  border-radius: 3px;
}

/* Compare Engines Button */
.btn-compare {
  margin-top: 12px;
  width: 100%;
  background: rgba(139, 92, 246, 0.15);
  border: 1px solid rgba(139, 92, 246, 0.35);
  color: #c4b5fd;
  padding: 9px 14px;
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-compare:hover {
  background: rgba(139, 92, 246, 0.28);
  border-color: rgba(139, 92, 246, 0.6);
  color: #fff;
  transform: translateY(-1px);
}

/* Benchmark Modal */
.benchmark-modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 200ms ease;
  padding: 20px;
}

.benchmark-modal.active {
  opacity: 1;
  pointer-events: auto;
}

.benchmark-modal-dialog {
  background: #0f172a;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 16px;
  width: 100%;
  max-width: 540px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.5);
  overflow: hidden;
}

.benchmark-modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.benchmark-modal-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
}

.btn-close {
  background: transparent;
  border: none;
  font-size: 1.5rem;
  color: var(--text-muted);
  cursor: pointer;
  line-height: 1;
}

.btn-close:hover {
  color: #fff;
}

.benchmark-modal-body {
  padding: 20px;
}

.benchmark-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 14px;
  line-height: 1.5;
}

.benchmark-status {
  font-size: 0.85rem;
  font-family: var(--font-mono);
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.2);
  padding: 8px 12px;
  border-radius: 6px;
  margin-bottom: 16px;
}

.benchmark-table-wrapper {
  overflow-x: auto;
}

.benchmark-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  text-align: left;
}

.benchmark-table th, .benchmark-table td {
  padding: 10px 12px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.benchmark-table th {
  color: var(--text-muted);
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.benchmark-table td {
  color: var(--text-primary);
  font-family: var(--font-mono);
}

.bm-gain {
  color: #10b981 !important;
  font-weight: 700;
}

.ai-win-toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: linear-gradient(135deg, #059669, #10b981);
  color: white;
  padding: 12px 24px;
  border-radius: 30px;
  font-weight: 600;
  font-size: 0.95rem;
  box-shadow: 0 10px 25px rgba(16, 185, 129, 0.45);
  z-index: 1000;
  opacity: 0;
  transition: all 300ms cubic-bezier(0.175, 0.885, 0.32, 1.275);
  pointer-events: none;
}

.ai-win-toast.visible {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* =============================================================================
   RESPONSIVE MOBILE, TABLET & TOUCH STYLES
   ============================================================================= */

/* Enhanced touch-friendly hit areas */
.btn {
  min-height: 42px;
}

.engine-tab {
  min-height: 38px;
}

.preset-btn {
  min-height: 38px;
}

#speed-slider {
  cursor: pointer;
  height: 24px;
}

/* Tablets and Single-Column View (< 860px) */
@media (max-width: 860px) {
  body {
    padding: 16px 12px;
    align-items: flex-start;
  }

  .app-container {
    max-width: 480px;
    gap: 16px;
  }

  .game-layout {
    grid-template-columns: 1fr;
    justify-items: center;
    gap: 18px;
  }

  .game-section {
    width: 100%;
    align-items: center;
  }

  .board-topbar {
    width: 100%;
    max-width: calc(var(--cell-size) * 4 + var(--grid-gap) * 3 + var(--board-padding) * 2);
  }

  .sidebar-section {
    width: 100%;
    max-width: calc(var(--cell-size) * 4 + var(--grid-gap) * 3 + var(--board-padding) * 2);
  }

  .hint-desktop {
    display: none;
  }
  .hint-mobile {
    display: inline;
  }
}

/* Standard Mobile Devices (< 520px) */
@media (max-width: 520px) {
  :root {
    --board-padding: 10px;
    --grid-gap: 10px;
    --cell-size: clamp(66px, calc((100vw - 60px) / 4.4), 84px);
    --board-radius: 10px;
    --tile-radius: 6px;
  }

  body {
    padding: 12px 8px;
    padding-top: max(12px, env(safe-area-inset-top));
    padding-bottom: max(16px, env(safe-area-inset-bottom));
  }

  .logo {
    font-size: 2.2rem;
  }

  .brand {
    gap: 8px;
  }

  .score-board {
    gap: 8px;
  }

  .score-card {
    padding: 6px 10px;
    min-width: 66px;
    border-radius: 8px;
  }

  .score-label {
    font-size: 0.64rem;
  }

  .score-value {
    font-size: 1.15rem;
  }

  .board-topbar {
    padding: 0 2px;
  }

  .subtitle {
    font-size: 0.84rem;
  }

  #btn-new-game {
    padding: 6px 12px;
    font-size: 0.8rem;
  }

  .speed-presets {
    grid-template-columns: repeat(2, 1fr);
    gap: 6px;
  }

  .telemetry-stat.mps-stat-card {
    grid-column: span 2;
  }

  .benchmark-modal {
    padding: 12px;
  }

  .benchmark-modal-dialog {
    border-radius: 14px;
    max-height: 92vh;
    display: flex;
    flex-direction: column;
  }

  .benchmark-modal-body {
    padding: 14px;
    overflow-y: auto;
  }

  .benchmark-table-wrapper {
    margin-bottom: 12px;
  }

  .benchmark-table th, .benchmark-table td {
    padding: 8px 6px;
    font-size: 0.76rem;
  }
}

/* Compact Mobile Devices (< 410px) */
@media (max-width: 410px) {
  :root {
    --board-padding: 8px;
    --grid-gap: 8px;
    --cell-size: clamp(56px, calc((100vw - 36px) / 4.35), 70px);
    --board-radius: 8px;
    --tile-radius: 5px;
  }

  body {
    padding: 8px 6px;
  }

  .brand {
    gap: 6px;
  }

  .logo {
    font-size: 1.85rem;
  }

  .badge {
    font-size: 0.62rem;
    padding: 2px 5px;
  }

  .score-card {
    padding: 4px 7px;
    min-width: 58px;
  }

  .score-label {
    font-size: 0.6rem;
  }

  .score-value {
    font-size: 1.05rem;
  }

  .tab-label-full {
    display: none;
  }

  .tab-label-short {
    display: inline;
  }

  .engine-tab {
    padding: 8px 2px;
    font-size: 0.72rem;
    gap: 3px;
  }

  .subtitle {
    font-size: 0.78rem;
  }

  #btn-new-game {
    padding: 5px 8px;
    font-size: 0.75rem;
  }
}

/* Touchscreen Device Press & Haptic Aesthetics */
@media (hover: none) and (pointer: coarse) {
  .btn:active, .engine-tab:active, .preset-btn:active {
    transform: scale(0.96);
    filter: brightness(1.15);
  }

  .hint-desktop {
    display: none;
  }
  .hint-mobile {
    display: inline;
  }
}