/* ============================================
   SONIC LAB v3 - THE NEW PLU STANDARD
   Professional Studio + Modern Interactions
   ============================================ */

:root {
  /* Dark Mode (Default) */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a24;
  --bg-elevated: #22222e;
  --bg-card: #181822;
  
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-active: rgba(255, 255, 255, 0.12);
  
  --accent-coral: #ff5a5a;
  --accent-coral-dim: rgba(255, 90, 90, 0.15);
  --accent-coral-light: #ff7a7a;
  --accent-teal: #00d4aa;
  --accent-teal-dim: rgba(0, 212, 170, 0.15);
  --accent-gold: #ffd700;
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.6);
  
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', monospace;
  --radius: 6px;
  --radius-lg: 12px;
  
  --header-height: 64px;
  --fab-size: 48px;
}

/* ============================================
   CLASSROOM MODE (Presentation/Beamer)
   Maximum readability for 10m+ distance
   ============================================ */

[data-classroom="true"] {
  /* Extra large base font for projector readability at distance */
  font-size: 24px;
}

[data-classroom="true"] .chapter-header {
  padding: 120px 5% 60px;
}

[data-classroom="true"] .chapter-header-inner,
[data-classroom="true"] .chapter-content {
  max-width: 100%;
  padding-left: 5%;
  padding-right: 5%;
}

[data-classroom="true"] .chapter-content {
  padding-top: 64px;
  padding-bottom: 64px;
  font-size: 1.4rem;
  line-height: 2;
}

[data-classroom="true"] .chapter-content p {
  font-size: 1.4rem;
  line-height: 2;
  margin-bottom: 24px;
  max-width: 900px;
}

[data-classroom="true"] .content-section h2 {
  font-size: 2.5rem;
  margin-bottom: 32px;
}

[data-classroom="true"] .content-section h2::before {
  width: 6px;
  height: 36px;
}

[data-classroom="true"] .content-section h3 {
  font-size: 1.8rem;
  margin: 48px 0 24px;
}

[data-classroom="true"] .chapter-title {
  font-size: 4rem;
  margin-bottom: 24px;
}

[data-classroom="true"] .chapter-lead {
  font-size: 1.6rem;
  max-width: 800px;
}

/* Lists larger */
[data-classroom="true"] .chapter-content ul,
[data-classroom="true"] .chapter-content ol {
  padding-left: 48px;
  margin-bottom: 32px;
}

[data-classroom="true"] .chapter-content li {
  font-size: 1.4rem;
  line-height: 2;
  margin-bottom: 16px;
}

/* Checklist items */
[data-classroom="true"] .checklist li {
  padding-left: 48px;
}

[data-classroom="true"] .checklist li::before {
  font-size: 1.4rem;
}

/* High contrast boxes */
[data-classroom="true"] .tip-box,
[data-classroom="true"] .practice-box,
[data-classroom="true"] .warning-box {
  border-width: 4px;
  padding: 40px 48px;
  margin: 40px 0;
  max-width: 900px;
}

[data-classroom="true"] .tip-box strong,
[data-classroom="true"] .practice-box h3,
[data-classroom="true"] .warning-box strong {
  font-size: 1.3rem;
}

/* Practice box lists */
[data-classroom="true"] .practice-box ol {
  margin-bottom: 0;
}

[data-classroom="true"] .practice-box li {
  margin-bottom: 20px;
}

/* Tables */
[data-classroom="true"] .freq-table th,
[data-classroom="true"] .freq-table td {
  padding: 20px 24px;
  font-size: 1.2rem;
}

/* Tool cards larger */
[data-classroom="true"] .tool-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px;
}

[data-classroom="true"] .tool-card {
  padding: 36px;
}

[data-classroom="true"] .tool-icon {
  width: 80px;
  height: 80px;
  font-size: 2.5rem;
}

[data-classroom="true"] .tool-name {
  font-size: 1.3rem;
}

[data-classroom="true"] .tool-desc {
  font-size: 1.1rem;
}

/* Hide distracting elements - BUT keep FAB buttons for mode switching! */
[data-classroom="true"] .chapter-progress,
/* Chapter Audio Widget (in module pages) */
.chapter-audio-widget {
  position: fixed;
  bottom: 24px;
  left: 24px;
  width: auto;
  min-width: 180px;
  max-width: 320px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  z-index: 100;
  overflow: hidden;
  transition: all 0.3s ease;
}

.chapter-audio-widget.expanded {
  width: 320px;
}

[data-classroom="true"] .chapter-audio-widget {
  display: none !important;
}

/* FAB buttons stay visible but MUCH larger for visibility */
[data-classroom="true"] .fab-container {
  gap: 24px;
  right: 5%;
  bottom: 48px;
}

[data-classroom="true"] .fab-btn {
  width: 80px;
  height: 80px;
  font-size: 2rem;
}

[data-classroom="true"] .fab-btn::before {
  font-size: 1.2rem;
  padding: 12px 20px;
  right: calc(100% + 16px);
}

/* Navigation footer larger */
[data-classroom="true"] .nav-footer {
  padding: 48px 5%;
  max-width: 100%;
}

[data-classroom="true"] .nav-btn {
  padding: 24px 48px;
  font-size: 1.4rem;
  border-radius: 12px;
}

/* Breadcrumb and header larger */
[data-classroom="true"] .chapter-breadcrumb {
  font-size: 1.2rem;
  margin-bottom: 24px;
}

[data-classroom="true"] .chapter-number {
  font-size: 1.1rem;
  padding: 8px 20px;
  margin-bottom: 24px;
}

/* Frequency demo larger */
[data-classroom="true"] .frequency-demo {
  padding: 48px;
  max-width: 900px;
}

[data-classroom="true"] .freq-display-large {
  font-size: 4rem;
}

[data-classroom="true"] .freq-label-large {
  font-size: 1.2rem;
}

[data-classroom="true"] .play-tone-btn {
  padding: 24px 48px;
  font-size: 1.3rem;
}

/* Hero section in index */
[data-classroom="true"] .hero {
  padding: 120px 5%;
}

[data-classroom="true"] .hero h1 {
  font-size: 5rem;
}

[data-classroom="true"] .hero-lead {
  font-size: 1.6rem;
  max-width: 800px;
}

[data-classroom="true"] .btn {
  padding: 20px 40px;
  font-size: 1.2rem;
}

/* Cooperation section */
[data-classroom="true"] .cooperation-section {
  padding: 80px 5%;
}

[data-classroom="true"] .cooperation-section h2 {
  font-size: 2.5rem;
}

[data-classroom="true"] .cooperation-lead {
  font-size: 1.4rem;
  max-width: 900px;
}

[data-classroom="true"] .pillar {
  padding: 40px;
}

[data-classroom="true"] .pillar h3 {
  font-size: 1.4rem;
}

[data-classroom="true"] .pillar p {
  font-size: 1.2rem;
}

/* Module cards */
[data-classroom="true"] .module-section {
  padding: 80px 5%;
  max-width: 100%;
}

[data-classroom="true"] .section-header h2 {
  font-size: 2.5rem;
}

[data-classroom="true"] .section-header p {
  font-size: 1.3rem;
}

[data-classroom="true"] .module-grid {
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: 32px;
}

[data-classroom="true"] .module-card {
  padding: 36px;
}

[data-classroom="true"] .module-title {
  font-size: 1.4rem;
}

[data-classroom="true"] .module-desc {
  font-size: 1.15rem;
}

[data-classroom="true"] .module-tag {
  font-size: 0.9rem;
  padding: 6px 14px;
}

/* Light Mode */
[data-theme="light"] {
  --bg-primary: #f8f9fa;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f3f4;
  --bg-elevated: #e8eaed;
  --bg-card: #ffffff;
  
  --text-primary: #1a1a2e;
  --text-secondary: #5f6368;
  --text-muted: #80868b;
  
  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-active: rgba(0, 0, 0, 0.15);
  
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.12);
}

/* ============================================
   BASE & RESET
   ============================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ============================================
   HEADER
   ============================================ */

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 1000;
}

[data-theme="light"] .header {
  background: rgba(255, 255, 255, 0.85);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 32px;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.5px;
}

.header-logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent-coral), var(--accent-teal));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
}

.header-logo-icon svg {
  width: 22px;
  height: 22px;
}

.header-logo-text span {
  color: var(--accent-coral);
}

/* Navigation */
.header-nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  padding: 8px 16px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: var(--radius);
  transition: all 0.2s ease;
}

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

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  margin-top: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 8px;
  min-width: 240px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.2s ease;
  box-shadow: var(--shadow-lg);
}

.nav-dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-item {
  display: block;
  padding: 12px 16px;
  border-radius: var(--radius);
  transition: background 0.2s ease;
}

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

.dropdown-item-name {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 4px;
}

.dropdown-item-desc {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Header Right */
.header-right {
  display: flex;
  align-items: center;
  gap: 16px;
}

.lang-switch {
  display: flex;
  background: var(--bg-tertiary);
  border-radius: 100px;
  padding: 4px;
}

.lang-btn {
  padding: 6px 12px;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 100px;
  color: var(--text-muted);
  transition: all 0.2s ease;
}

.lang-btn.active {
  background: var(--accent-coral);
  color: white;
}

.btn-support {
  padding: 8px 20px;
  background: var(--accent-coral);
  color: white;
  font-weight: 600;
  font-size: 0.85rem;
  border-radius: 100px;
  transition: all 0.2s ease;
}

.btn-support:hover {
  background: var(--accent-coral-light);
  transform: translateY(-1px);
}

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
}

.mobile-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
}

/* ============================================
   AUDIO WIDGET
   ============================================ */

.audio-widget {
  position: fixed;
  bottom: 24px;
  left: 24px;
  width: auto;
  min-width: 180px;
  max-width: 320px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  z-index: 100;
  overflow: hidden;
  transition: all 0.3s ease;
}

.audio-widget.expanded {
  width: 320px;
}

.audio-widget:hover {
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

.audio-widget-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-subtle);
}

.audio-widget-title {
  font-weight: 700;
  font-size: 0.9rem;
}

.audio-widget-toggle {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 4px;
}

.audio-widget-content {
  padding: 16px;
}

.audio-widget.collapsed .audio-widget-content {
  display: none;
}

/* Tabs */
.audio-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.audio-tab {
  flex: 1;
  padding: 8px 16px;
  background: var(--bg-tertiary);
  border: none;
  border-radius: var(--radius);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.8rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.audio-tab.active {
  background: var(--accent-coral);
  color: white;
}

.audio-tab-content {
  display: none;
}

.audio-tab-content.active {
  display: block;
}

/* Generator Tab */
.freq-display {
  text-align: center;
  margin-bottom: 16px;
}

.freq-value {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-coral);
}

.freq-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.waveform-container {
  height: 100px;
  background: var(--bg-primary);
  border-radius: var(--radius);
  margin-bottom: 16px;
  overflow: hidden;
}

#waveformCanvas {
  width: 100%;
  height: 100%;
}

.freq-slider {
  width: 100%;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 3px;
  outline: none;
  -webkit-appearance: none;
  margin-bottom: 16px;
}

.freq-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  background: var(--accent-coral);
  border-radius: 50%;
  cursor: pointer;
}

.gen-controls {
  display: flex;
  gap: 8px;
}

.gen-btn {
  flex: 1;
  padding: 8px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  color: var(--text-secondary);
  font-size: 0.7rem;
  font-weight: 700;
  font-family: var(--font-mono);
  cursor: pointer;
  transition: all 0.2s ease;
}

.gen-btn.active {
  background: var(--accent-coral);
  border-color: var(--accent-coral);
  color: white;
}

.play-btn {
  width: 100%;
  padding: 12px;
  background: var(--accent-teal);
  border: none;
  border-radius: var(--radius);
  color: white;
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s ease;
  margin-top: 12px;
}

.play-btn:hover {
  background: #00b894;
}

/* Player Tab */
.player-upload {
  border: 2px dashed var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
}

.player-upload:hover {
  border-color: var(--accent-coral);
  background: var(--accent-coral-dim);
}

.player-upload-icon {
  font-size: 2rem;
  margin-bottom: 8px;
}

.player-upload-text {
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 4px;
}

.player-upload-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

#audioFileInput {
  display: none;
}

.player-track-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.track-name {
  font-weight: 600;
  font-size: 0.9rem;
}

.track-time {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.progress-container {
  height: 4px;
  background: var(--bg-tertiary);
  border-radius: 2px;
  cursor: pointer;
  margin-bottom: 16px;
}

.progress-bar {
  height: 100%;
  background: var(--accent-coral);
  border-radius: 2px;
  width: 0%;
  transition: width 0.1s linear;
}

.player-controls {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  margin-bottom: 12px;
}

.player-btn {
  width: 40px;
  height: 40px;
  background: var(--bg-tertiary);
  border: none;
  border-radius: 50%;
  color: var(--text-primary);
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}

.player-btn:hover {
  background: var(--border-active);
}

.player-btn.play {
  width: 48px;
  height: 48px;
  background: var(--accent-coral);
}

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

.volume-control {
  display: flex;
  align-items: center;
  gap: 8px;
}

.volume-icon {
  font-size: 0.9rem;
}

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

.volume-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  background: var(--accent-teal);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 0 8px rgba(0, 212, 170, 0.4);
}

.volume-slider::-webkit-slider-thumb:hover {
  box-shadow: 0 0 12px rgba(0, 212, 170, 0.6);
  transform: scale(1.1);
}

.volume-slider::-moz-range-thumb {
  width: 16px;
  height: 16px;
  background: var(--accent-teal);
  border-radius: 50%;
  cursor: pointer;
  border: none;
  box-shadow: 0 0 8px rgba(0, 212, 170, 0.4);
}

/* Audio Effects Section */
.audio-effects {
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--border-subtle);
}

.effects-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  font-weight: 700;
  font-size: 0.9rem;
}

.effects-icon {
  font-size: 1.1rem;
}

.effects-title {
  color: var(--text-primary);
}

.effect-group {
  margin-bottom: 16px;
}

.effect-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

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

.effect-value {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--accent-coral);
  font-weight: 700;
}

.filter-buttons {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}

.filter-btn {
  padding: 6px 12px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  color: var(--text-secondary);
  font-size: 0.7rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.filter-btn:hover {
  border-color: var(--border-active);
}

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

.filter-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-style: italic;
}

.effect-hint {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.effect-slider {
  width: 100%;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 3px;
  outline: none;
  -webkit-appearance: none;
}

.effect-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  background: var(--accent-teal);
  border-radius: 50%;
  cursor: pointer;
}

/* ============================================
   FLOATING ACTION BUTTONS
   ============================================ */

.fab-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  z-index: 100;
}

.fab-btn {
  width: var(--fab-size);
  height: var(--fab-size);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 50%;
  color: var(--text-primary);
  font-size: 1.1rem;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  position: relative;
}

.fab-btn:hover {
  background: var(--bg-elevated);
  transform: scale(1.1);
}

.fab-btn::before {
  content: attr(data-tooltip);
  position: absolute;
  right: calc(100% + 12px);
  background: var(--bg-card);
  padding: 6px 12px;
  border-radius: var(--radius);
  font-size: 0.75rem;
  font-weight: 600;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s ease;
  border: 1px solid var(--border-subtle);
}

.fab-btn:hover::before {
  opacity: 1;
  visibility: visible;
}

/* ============================================
   HERO SECTION
   ============================================ */

.main {
  padding-top: var(--header-height);
}

.hero {
  padding: 80px 24px;
  max-width: 1100px;
  margin: 0 auto;
  text-align: center;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent-coral-dim);
  color: var(--accent-coral);
  padding: 8px 16px;
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 700;
  margin-bottom: 24px;
}

.hero-tag-dot {
  width: 8px;
  height: 8px;
  background: var(--accent-coral);
  border-radius: 50%;
  animation: pulse-dot 2s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 24px;
  letter-spacing: -2px;
}

.hero h1 span {
  background: linear-gradient(135deg, var(--accent-coral), var(--accent-teal));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-lead {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 32px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 32px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 100px;
  font-weight: 700;
  font-size: 0.95rem;
  transition: all 0.2s ease;
}

.btn-primary {
  background: var(--accent-coral);
  color: white;
}

.btn-primary:hover {
  background: var(--accent-coral-light);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
}

.btn-secondary:hover {
  background: var(--bg-elevated);
  border-color: var(--border-active);
}

.hero-tech {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.tech-item {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.tech-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.tech-dot.open {
  background: var(--accent-teal);
}

.tech-dot.ai {
  background: var(--accent-coral);
}

/* ============================================
   COOPERATION SECTION
   ============================================ */

.cooperation-section {
  padding: 80px 24px;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.cooperation-content {
  max-width: 1100px;
  margin: 0 auto;
}

.cooperation-section h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 16px;
  text-align: left;
}

.cooperation-lead {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 700px;
  margin-bottom: 40px;
  line-height: 1.7;
}

.cooperation-pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-bottom: 40px;
}

@media (max-width: 900px) {
  .cooperation-pillars {
    grid-template-columns: 1fr;
  }
}

.pillar {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  padding: 28px;
  transition: all 0.3s ease;
}

.pillar:hover {
  border-color: var(--border-active);
}

.pillar h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--accent-coral);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.pillar p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}

.cooperation-cta {
  margin-top: 8px;
}

/* ============================================
   MODULE SECTION
   ============================================ */

.module-section {
  padding: 60px 24px;
  max-width: 1100px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 48px;
}

.section-header h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 12px;
}

.section-header p {
  color: var(--text-secondary);
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.module-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: all 0.3s ease;
  position: relative;
  display: block;
  cursor: pointer;
}

.module-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent-teal), transparent);
  opacity: 1;
  transition: all 0.3s ease;
}

.module-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-active);
  box-shadow: var(--shadow-md);
}

.module-card:hover::before {
  background: linear-gradient(90deg, var(--accent-coral), transparent);
  height: 3px;
  opacity: 1;
}

.module-card.highlight::before {
  background: linear-gradient(90deg, var(--accent-teal), transparent);
  opacity: 1;
}

.module-card.highlight:hover::before {
  background: linear-gradient(90deg, var(--accent-coral), transparent);
}

.module-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.module-number {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  padding: 4px 10px;
  background: var(--bg-tertiary);
  border-radius: var(--radius);
}

.module-card.highlight .module-number {
  background: var(--accent-teal-dim);
  color: var(--accent-teal);
}

.module-title {
  font-size: 1.15rem;
  font-weight: 700;
  flex: 1;
}

.module-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 16px;
}

.module-meta {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.module-tag {
  font-size: 0.7rem;
  font-weight: 600;
  padding: 4px 10px;
  background: var(--bg-tertiary);
  color: var(--text-muted);
  border-radius: 100px;
  font-family: var(--font-mono);
}

.module-tag.highlight {
  background: var(--accent-coral-dim);
  color: var(--accent-coral);
}

.module-title .core {
  color: var(--accent-coral);
  font-weight: 700;
}

/* ============================================
   FOOTER
   ============================================ */

.footer {
  padding: 40px 24px;
  border-top: 1px solid var(--border-subtle);
  text-align: center;
}

.footer-links {
  display: flex;
  gap: 24px;
  justify-content: center;
  margin-bottom: 16px;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.85rem;
  text-decoration: none;
}

.footer-links a:hover {
  color: var(--text-primary);
}

.footer-copy {
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 1024px) {
  .header-nav {
    display: none;
  }
  
  .mobile-toggle {
    display: flex;
    margin-right: 8px;
    padding: 10px;
  }
  
  .audio-widget {
    left: 16px;
    bottom: 80px;
    width: auto;
    min-width: 160px;
    max-width: calc(100vw - 100px);
  }
  
  .audio-widget.expanded {
    width: auto;
    max-width: calc(100vw - 32px);
  }
  
  .fab-container {
    right: 16px;
    bottom: 16px;
  }

@media (max-width: 640px) {
  .header-right {
    display: none;
  }
  
  .hide-mobile {
    display: none;
  }
  
  /* Mobile Player Icon in Header - only visible on mobile */
  .mobile-player-icon {
    display: flex !important;
    margin-left: auto;
    margin-right: 12px;
    font-size: 1.4rem;
    padding: 8px;
    border-radius: 50%;
    transition: background 0.2s ease;
    color: var(--text-primary);
    text-decoration: none;
  }
  
  /* ============================================
     MOBILE TABLES - Clean Horizontal Scroll
     ============================================ */
  
  /* Make all tables horizontally scrollable */
  .content-section table,
  .platform-table,
  .freq-table,
  .param-table,
  table {
    display: block;
    width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    border-radius: 8px;
    background: var(--bg-card);
  }
  
  /* Ensure table has minimum width for scroll */
  .content-section table tbody,
  .platform-table tbody,
  .freq-table tbody,
  .param-table tbody,
  table tbody {
    display: table;
    min-width: 600px;
    width: 100%;
  }
  
  /* Header styling - no sticky */
  .content-section table th,
  .platform-table th,
  .freq-table th,
  .param-table th,
  table th {
    padding: 12px 16px;
    text-align: left;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    white-space: nowrap;
  }
  
  /* Cell styling */
  .content-section table td,
  .platform-table td,
  .freq-table td,
  .param-table td,
  table td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-subtle);
    white-space: nowrap;
    color: var(--text-secondary);
  }
  
  /* Last row no border */
  .content-section table tr:last-child td,
  .platform-table tr:last-child td,
  .freq-table tr:last-child td,
  .param-table tr:last-child td,
  table tr:last-child td {
    border-bottom: none;
  }
  
  /* Hover effect */
  .content-section table tr:hover td,
  .platform-table tr:hover td,
  .freq-table tr:hover td,
  .param-table tr:hover td,
  table tr:hover td {
    background: var(--bg-tertiary);
    color: var(--text-primary);
  }
  }
  
  .mobile-player-icon:hover {
    background: rgba(255, 255, 255, 0.1);
  }
  
  .hero-actions {
    flex-direction: column;
    align-items: center;
  }
  
  .btn {
    width: 100%;
    max-width: 280px;
    justify-content: center;
  }
  
  .module-grid {
    grid-template-columns: 1fr;
  }
  
  .hero-tech {
    flex-direction: column;
    gap: 8px;
  }
  
  /* FAB Buttons: Fixed at bottom with proper spacing */
  .fab-container {
    position: fixed;
    bottom: 24px;
    left: 50%;
    right: auto;
    transform: translateX(-50%);
    flex-direction: row;
    gap: 8px;
    z-index: 1000;
    background: rgba(30, 30, 30, 0.95);
    backdrop-filter: blur(12px);
    padding: 10px 20px;
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  }
  
  /* Light Mode Anpassungen für FAB Container */
  [data-theme="light"] .fab-container {
    background: rgba(255, 255, 255, 0.95);
    border: 1px solid rgba(0, 0, 0, 0.1);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
  }
  
  .fab-btn {
    width: 36px;
    height: 36px;
    font-size: 1rem;
    background: transparent;
    border: none;
    box-shadow: none;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  .fab-btn:hover {
    transform: scale(1.1);
    background: rgba(255, 255, 255, 0.15);
  }
  
  [data-theme="light"] .fab-btn:hover {
    background: rgba(0, 0, 0, 0.1);
  }
  
  .fab-btn.active {
    background: var(--accent-primary);
    color: var(--bg-primary);
  }
  
  /* Hide tooltips on mobile (no hover) */
  .fab-btn::before {
    display: none;
  }
  
  /* Audio widget: Hidden on mobile - use standalone player instead */
  .audio-widget,
  #audioWidget,
  .chapter-audio-widget {
    display: none !important;
  }
  
  /* Footer: Extra padding for FAB button bar */
  .footer {
    padding-bottom: 110px;
  }
  
  /* Main content: Extra bottom padding */
  main {
    padding-bottom: 40px;
  }
  
  /* Dropdown Menu: Modal-style on mobile for better visibility */
  .dropdown-menu {
    position: fixed;
    top: 72px;
    left: 16px;
    right: 16px;
    width: auto;
    min-width: auto;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
    z-index: 9999;
    background: var(--bg-card);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    padding: 12px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
  }
  
  /* Ensure dropdown items are touch-friendly */
  .dropdown-item {
    padding: 16px;
    margin-bottom: 4px;
  }
  
  .dropdown-item:last-child {
    margin-bottom: 0;
  }
  
  .dropdown-item-name {
    font-size: 1rem;
  }
  
  .dropdown-item-desc {
    font-size: 0.85rem;
  }
  
  /* Ensure dropdown is visible when parent is hovered */
  .nav-dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  
  /* Click area for dropdown */
  .nav-dropdown {
    position: relative;
  }

@media (max-width: 480px) {
  .header {
    padding: 0 16px;
  }
  
  /* Show logo text on mobile as requested */
  .header-logo-text {
    display: inline;
    font-size: 0.9rem;
  }
}