/* ============ Base Styles ============ */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: background var(--transition-speed), color var(--transition-speed);
  user-select: none;
  -webkit-user-select: none;
}

/* ============ App Layout ============ */
.app-container {
  display: flex;
  width: 100%;
  height: 100vh;
}

/* ============ Sidebar ============ */
.sidebar {
  width: 280px;
  min-width: 280px;
  height: 100%;
  background: var(--bg-panel);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-right: 1px solid rgba(255, 255, 255, 0.06);
  display: flex;
  flex-direction: column;
  padding: 20px;
  gap: 16px;
  overflow-y: auto;
  z-index: 10;
  box-shadow: var(--shadow-panel);
}

.sidebar-header {
  text-align: center;
  padding-bottom: 16px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.sidebar-header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 1px;
}

.sidebar-header .subtitle {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* Sidebar Sections */
.sidebar-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.sidebar-section h3 {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--text-secondary);
  margin-bottom: 2px;
}

/* Theme Selector */
.theme-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

.theme-btn {
  padding: 8px 10px;
  border: 2px solid var(--border-tile);
  border-radius: 8px;
  background: var(--bg-tile);
  color: var(--text-primary);
  font-size: 0.72rem;
  cursor: pointer;
  transition: all 0.25s ease;
  text-align: center;
}

.theme-btn:hover {
  border-color: var(--accent-primary);
  box-shadow: 0 0 12px var(--accent-glow);
  transform: translateY(-1px);
}

.theme-btn.active {
  border-color: var(--accent-primary);
  background: var(--btn-bg);
  color: var(--btn-text);
  box-shadow: 0 0 16px var(--accent-glow);
}

/* Category Selector */
.category-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

.category-btn {
  padding: 8px 10px;
  border: 2px solid var(--border-tile);
  border-radius: 8px;
  background: var(--bg-tile);
  color: var(--text-primary);
  font-size: 0.72rem;
  cursor: pointer;
  transition: all 0.25s ease;
  text-align: center;
}

.category-btn:hover {
  border-color: var(--accent-secondary);
  box-shadow: 0 0 10px rgba(0, 255, 136, 0.3);
  transform: translateY(-1px);
}

.category-btn.active {
  border-color: var(--accent-secondary);
  background: linear-gradient(135deg, rgba(0, 255, 136, 0.15), rgba(0, 255, 136, 0.05));
  box-shadow: 0 0 12px rgba(0, 255, 136, 0.3);
}

/* Mode Toggle */
.mode-toggle {
  display: flex;
  gap: 4px;
  background: var(--bg-tile);
  border-radius: 8px;
  padding: 3px;
}

.mode-btn {
  flex: 1;
  padding: 8px;
  border: none;
  border-radius: 6px;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.72rem;
  cursor: pointer;
  transition: all 0.25s ease;
}

.mode-btn.active {
  background: var(--btn-bg);
  color: var(--btn-text);
}

/* Music Section */
.music-controls {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.music-select {
  width: 100%;
  padding: 8px;
  border: 2px solid var(--border-tile);
  border-radius: 8px;
  background: var(--bg-tile);
  color: var(--text-primary);
  font-size: 0.72rem;
  cursor: pointer;
  outline: none;
}

.music-select:focus {
  border-color: var(--accent-primary);
}

.music-select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.loop-toggle {
  display: flex;
  gap: 4px;
}

.loop-btn {
  flex: 1;
  padding: 6px;
  border: 1px solid var(--border-tile);
  border-radius: 6px;
  background: var(--bg-tile);
  color: var(--text-secondary);
  font-size: 0.65rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.loop-btn.active {
  background: var(--btn-bg);
  color: var(--btn-text);
  border-color: var(--accent-primary);
}

.volume-slider {
  -webkit-appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 2px;
  background: var(--border-tile);
  outline: none;
  margin-top: 4px;
}

.volume-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent-primary);
  cursor: pointer;
  box-shadow: 0 0 8px var(--accent-glow);
}

/* Game Controls */
.game-btn {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 10px;
  background: var(--btn-bg);
  color: var(--btn-text);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.25s ease;
  letter-spacing: 0.5px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
}

.game-btn:hover {
  background: var(--btn-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
}

.game-btn:active {
  transform: translateY(0);
}

.game-btn.secondary {
  background: var(--bg-tile);
  border: 2px solid var(--border-tile);
  color: var(--text-primary);
}

.game-btn.secondary:hover {
  border-color: var(--accent-primary);
  box-shadow: 0 0 14px var(--accent-glow);
}

/* ============ Main Game Area ============ */
.main-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
  position: relative;
  overflow: hidden;
}

/* Stats Bar */
.stats-bar {
  display: flex;
  gap: 24px;
  margin-bottom: 16px;
  align-items: center;
}

.stat-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--bg-panel);
  border-radius: 20px;
  font-size: 0.85rem;
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.2);
}

.stat-label {
  color: var(--text-secondary);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.stat-value {
  color: var(--text-accent);
  font-weight: 700;
  font-size: 1.1rem;
  font-variant-numeric: tabular-nums;
}

/* Board Container */
.board-wrapper {
  position: relative;
  display: inline-block;
}

.board-container {
  display: grid;
  gap: var(--grid-gap);
  padding: 12px;
  background: var(--bg-panel);
  border-radius: 16px;
  box-shadow: var(--shadow-panel);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

/* Canvas Overlay for effects */
.effect-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 5;
}

/* ============ Tile Styles ============ */
.tile {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  background: var(--bg-tile);
  border: 2px solid var(--border-tile);
  border-radius: var(--tile-radius);
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  box-shadow: var(--shadow-tile);
  z-index: 1;
}

.tile:hover {
  border-color: var(--border-tile-hover);
  box-shadow: 0 0 16px var(--accent-glow);
  transform: translateY(-3px);
  z-index: 2;
}

.tile.selected {
  border-color: var(--border-tile-selected);
  background: var(--bg-tile-selected);
  box-shadow: 0 0 20px var(--accent-glow), inset 0 0 20px rgba(255, 255, 255, 0.1);
  transform: translateY(-4px) scale(1.08);
  z-index: 3;
  animation: pulse-glow 0.8s ease-in-out infinite;
}

.tile.matched {
  animation: match-pop 0.5s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

.tile.hint-glow {
  animation: hint-pulse 0.6s ease-in-out infinite;
  border-color: var(--accent-secondary) !important;
  box-shadow: 0 0 20px rgba(0, 255, 136, 0.6) !important;
}

.tile.empty {
  background: transparent;
  border-color: transparent;
  box-shadow: none;
  cursor: default;
  pointer-events: none;
}

.tile.removing {
  animation: tile-disappear 0.4s ease-in forwards;
}

/* ============ Animations ============ */
@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 20px var(--accent-glow), inset 0 0 20px rgba(255, 255, 255, 0.1); }
  50% { box-shadow: 0 0 35px var(--accent-glow), inset 0 0 30px rgba(255, 255, 255, 0.2); }
}

@keyframes match-pop {
  0% { transform: scale(1); opacity: 1; }
  40% { transform: scale(1.3); opacity: 1; }
  100% { transform: scale(0); opacity: 0; }
}

@keyframes hint-pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); }
}

@keyframes tile-disappear {
  0% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.2) rotateY(90deg); opacity: 0.5; }
  100% { transform: scale(0) rotateY(180deg); opacity: 0; }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes shimmer {
  0% { background-position: -200% center; }
  100% { background-position: 200% center; }
}

/* ============ Overlay / Modal ============ */
.overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: var(--overlay-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  animation: fadeIn 0.3s ease;
}

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

.modal {
  background: var(--bg-panel);
  border-radius: 20px;
  padding: 40px;
  text-align: center;
  box-shadow: var(--shadow-panel), 0 0 60px var(--accent-glow);
  max-width: 420px;
  width: 90%;
  animation: fadeInUp 0.5s ease;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.modal h2 {
  font-size: 1.8rem;
  margin-bottom: 12px;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.modal p {
  color: var(--text-secondary);
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.modal .score-display {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent-primary);
  text-shadow: 0 0 20px var(--accent-glow);
  margin: 16px 0;
}

.modal .btn-group {
  display: flex;
  gap: 12px;
  justify-content: center;
  margin-top: 20px;
}

.modal .btn-group .game-btn {
  width: auto;
  padding: 10px 28px;
}

/* ============ Combo Indicator ============ */
.combo-indicator {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 2.5rem;
  font-weight: 900;
  pointer-events: none;
  z-index: 50;
  animation: combo-rise 1.2s ease-out forwards;
  text-shadow: 0 0 30px var(--accent-glow);
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

@keyframes combo-rise {
  0% { opacity: 1; transform: translate(-50%, -50%) scale(0.5); }
  30% { opacity: 1; transform: translate(-50%, -80%) scale(1.2); }
  100% { opacity: 0; transform: translate(-50%, -150%) scale(0.8); }
}

/* ============ Responsive ============ */
@media (max-width: 1024px) {
  .app-container {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
    min-width: 100%;
    height: auto;
    max-height: 40vh;
    flex-shrink: 0;
  }
  .main-area {
    padding: 10px;
  }
  .tile {
    width: 38px;
    height: 38px;
    font-size: 1.2rem;
  }
  .board-container {
    gap: 3px;
    padding: 8px;
  }
}

@media (max-width: 640px) {
  .tile {
    width: 30px;
    height: 30px;
    font-size: 1rem;
    border-radius: 6px;
  }
  .board-container {
    gap: 2px;
    padding: 6px;
  }
  .stats-bar {
    gap: 10px;
  }
  .stat-item {
    padding: 6px 10px;
    font-size: 0.7rem;
  }
}