*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg-primary: #0d0d0d;
  --bg-secondary: #1a1a1a;
  --bg-card: #242424;
  --bg-hover: #2e2e2e;
  --text-primary: #f0f0f0;
  --text-secondary: #a0a0a0;
  --accent: #ff6b35;
  --accent-hover: #ff8555;
  --accent-dim: #cc4d1a;
  --beat-active: #ff6b35;
  --beat-inactive: #333;
  --success: #4caf50;
  --border: #333;
  --radius: 8px;
  --radius-lg: 12px;
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --transition: 0.2s ease;
}

html {
  font-size: 16px;
}

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.5;
  -webkit-tap-highlight-color: transparent;
}

/* Header */
.app-header {
  background: var(--bg-secondary);
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
}

.app-nav {
  display: flex;
  gap: 0.25rem;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 500;
  transition: background var(--transition), color var(--transition);
}

.nav-link:hover, .nav-link:focus {
  background: var(--bg-card);
  color: var(--text-primary);
}

.nav-link.active {
  background: var(--accent);
  color: #fff;
}

/* Main */
.app-main {
  flex: 1;
  max-width: 900px;
  width: 100%;
  margin: 0 auto;
  padding: 1rem;
}

/* Views */
.view {
  display: none;
}

.view.active {
  display: block;
}

.view-content h2 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

/* Home */
.home-subtitle {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  font-size: 1.05rem;
}

.home-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
}

.home-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  text-decoration: none;
  color: var(--text-primary);
  border: 1px solid var(--border);
  transition: background var(--transition), transform var(--transition), border-color var(--transition);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.home-card:hover {
  background: var(--bg-hover);
  transform: translateY(-2px);
  border-color: var(--accent);
}

.home-card-icon {
  font-size: 2.5rem;
  margin-bottom: 0.75rem;
}

.home-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

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

/* Practice */
.practice-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 600px) {
  .practice-layout {
    grid-template-columns: 1fr 1fr;
  }
}

.control-group {
  margin-bottom: 1rem;
}

.control-group label {
  display: block;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.35rem;
  font-weight: 500;
}

.dance-select {
  width: 100%;
  padding: 0.65rem;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 1rem;
  cursor: pointer;
}

.dance-select:focus {
  border-color: var(--accent);
  outline: none;
}

.bpm-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.bpm-slider {
  flex: 1;
  height: 6px;
  -webkit-appearance: none;
  appearance: none;
  background: var(--border);
  border-radius: 3px;
  outline: none;
}

.bpm-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg-primary);
}

.bpm-slider::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg-primary);
}

#bpm-display {
  color: var(--accent);
  font-weight: 700;
  font-size: 1.1rem;
}

.transport-group {
  display: flex;
  gap: 0.75rem;
}

/* Buttons */
.btn {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.6rem 1.2rem;
  font-size: 1rem;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  font-weight: 500;
  touch-action: manipulation;
}

.btn:hover, .btn:focus {
  background: var(--bg-hover);
  border-color: var(--accent);
}

.btn-sm {
  padding: 0.4rem 0.8rem;
  font-size: 1.2rem;
  font-weight: 700;
  min-width: 44px;
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-play {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  min-width: 100px;
  font-size: 1.1rem;
}

.btn-play:hover {
  background: var(--accent-hover);
}

.btn-play.playing {
  background: var(--accent-dim);
}

.btn-stop {
  min-width: 100px;
}

.btn-tap {
  width: 100%;
  min-height: 60px;
  font-size: 1.2rem;
}

.btn-back {
  background: transparent;
  border: none;
  color: var(--accent);
  padding: 0.5rem 0;
  font-size: 1rem;
  cursor: pointer;
  margin-bottom: 1rem;
}

.btn-back:hover {
  color: var(--accent-hover);
}

/* Beat indicators */
.beat-indicators {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.beat-dot {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--beat-inactive);
  transition: background var(--transition), transform 0.1s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
}

.beat-dot.active {
  background: var(--beat-active);
  transform: scale(1.15);
}

.beat-dot.strong {
  width: 56px;
  height: 56px;
}

.beat-counter {
  font-size: 3rem;
  font-weight: 700;
  text-align: center;
  color: var(--accent);
  margin: 1rem 0;
  font-variant-numeric: tabular-nums;
}

.current-dance-info {
  text-align: center;
}

.dance-name {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

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

/* Analysis */
.analysis-inputs {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-bottom: 1.5rem;
}

.btn-record {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  min-height: 56px;
  font-size: 1.1rem;
  width: 100%;
}

.btn-record.recording {
  background: #c62828;
  border-color: #c62828;
  animation: pulse 1.5s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.status-text {
  display: block;
  margin-top: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.file-input {
  display: block;
  width: 100%;
  padding: 0.6rem;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.9rem;
}

.url-input-group {
  margin-top: 0.5rem;
}

.url-row {
  display: flex;
  gap: 0.5rem;
}

.url-input {
  flex: 1;
  padding: 0.65rem;
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.9rem;
  min-width: 0;
}

.url-input:focus {
  border-color: var(--accent);
  outline: none;
}

.btn-analyze-url {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  white-space: nowrap;
  min-height: 44px;
}

.btn-analyze-url:hover {
  background: var(--accent-hover);
}

.btn-analyze-url:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.analysis-progress {
  text-align: center;
  padding: 2rem;
  color: var(--text-secondary);
}

.analysis-results {
  margin-top: 1.5rem;
}

.result-section {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  margin-bottom: 1rem;
  border: 1px solid var(--border);
}

.result-section h3 {
  font-size: 1.05rem;
  margin-bottom: 0.75rem;
  color: var(--accent);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 0.75rem;
}

.feature-item {
  background: var(--bg-secondary);
  padding: 0.75rem;
  border-radius: var(--radius);
  text-align: center;
}

.feature-item .label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.feature-item .value {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-top: 0.25rem;
}

.suggestion-item {
  background: var(--bg-secondary);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  margin-bottom: 0.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  transition: background var(--transition);
}

.suggestion-item:hover {
  background: var(--bg-hover);
}

.suggestion-item .name {
  font-weight: 600;
}

.suggestion-item .confidence {
  color: var(--accent);
  font-weight: 700;
}

.suggestion-item .explanation {
  display: block;
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 0.2rem;
}

/* Library */
.library-filters {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.filter-btn {
  background: var(--bg-card);
  color: var(--text-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.5rem 1rem;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
  touch-action: manipulation;
}

.filter-btn:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.filter-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.library-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
}

.library-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  touch-action: manipulation;
}

.library-card:hover {
  background: var(--bg-hover);
  border-color: var(--accent);
}

.library-card .card-name {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.35rem;
}

.library-card .card-meta {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

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

.library-card .card-category {
  display: inline-block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  margin-bottom: 0.35rem;
}

/* Dance Detail */
#dance-detail-content h2 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.detail-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.detail-meta-item {
  background: var(--bg-card);
  padding: 0.75rem;
  border-radius: var(--radius);
  text-align: center;
  border: 1px solid var(--border);
}

.detail-meta-item .label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.detail-meta-item .value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
  margin-top: 0.25rem;
}

.detail-section {
  margin-bottom: 1.25rem;
}

.detail-section h3 {
  font-size: 1.05rem;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.detail-section p {
  color: var(--text-secondary);
  line-height: 1.7;
}

.detail-section ul {
  list-style: none;
  padding: 0;
}

.detail-section ul li {
  color: var(--text-secondary);
  padding: 0.25rem 0;
  padding-left: 1rem;
  position: relative;
}

.detail-section ul li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* Footer */
.app-footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--text-secondary);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
}

/* Utility */
.hidden {
  display: none !important;
}