/* ================================================================
   VibeAcademy — Design System
   Eine generative Lernplattform mit dynamischem Theming
   ================================================================ */

/* ========== FONTS ========== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Space+Grotesk:wght@400;500;600;700&display=swap');

/* ========== THEME: Cosmic Dark (Default) ========== */
:root {
  --bg-base: #070b14;
  --bg-surface: rgba(255, 255, 255, 0.04);
  --bg-surface-hover: rgba(255, 255, 255, 0.08);
  --bg-elevated: rgba(255, 255, 255, 0.06);
  --bg-overlay: rgba(7, 11, 20, 0.88);
  --bg-input: rgba(255, 255, 255, 0.05);

  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-medium: rgba(255, 255, 255, 0.12);
  --border-strong: rgba(255, 255, 255, 0.22);

  --primary: #a855f7;
  --primary-light: #c084fc;
  --primary-dark: #7c3aed;
  --primary-glow: rgba(168, 85, 247, 0.25);
  --secondary: #06b6d4;
  --secondary-light: #22d3ee;
  --secondary-glow: rgba(6, 182, 212, 0.2);
  --accent: #f59e0b;
  --accent-glow: rgba(245, 158, 11, 0.2);
  --success: #10b981;
  --success-glow: rgba(16, 185, 129, 0.2);
  --error: #f43f5e;
  --error-glow: rgba(244, 63, 94, 0.2);
  --warning: #f59e0b;

  --text-primary: rgba(255, 255, 255, 0.93);
  --text-secondary: rgba(255, 255, 255, 0.65);
  --text-muted: rgba(255, 255, 255, 0.35);
  --text-inverse: #070b14;

  --gradient-primary: linear-gradient(135deg, #7c3aed, #a855f7, #c084fc);
  --gradient-secondary: linear-gradient(135deg, #0891b2, #06b6d4, #22d3ee);
  --gradient-accent: linear-gradient(135deg, #d97706, #f59e0b, #fbbf24);
  --gradient-surface: linear-gradient(135deg, rgba(255,255,255,0.06) 0%, rgba(255,255,255,0.015) 100%);

  --font-heading: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;

  --space-2xs: 0.125rem;
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 40px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 30px var(--primary-glow);

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-fast: 150ms var(--ease-out);
  --transition-base: 300ms var(--ease-out);
  --transition-slow: 500ms var(--ease-out);

  --blob-1: var(--primary);
  --blob-2: var(--secondary);
}

/* Themes (nature-green, neon-cyber, cosmic-dark) are dynamically loaded from the user's JSON profile and injected into the document root. No hardcoded theme CSS overrides are allowed here. */

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

/* ========== CUSTOM SCROLLBAR ========== */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--border-medium);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover { background: var(--border-strong); }

/* ========== BODY & BACKGROUND ========== */
body {
  font-family: var(--font-body);
  background: var(--bg-base);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}

/* Ambient glow blobs */
body::before,
body::after {
  content: '';
  position: fixed;
  border-radius: 50%;
  filter: blur(120px);
  opacity: 0.12;
  pointer-events: none;
  z-index: 0;
  transition: background 1s ease;
}
body::before {
  width: 50vw;
  height: 50vw;
  max-width: 700px;
  max-height: 700px;
  background: var(--blob-1);
  top: -15%;
  right: -10%;
  animation: blobDrift1 25s ease-in-out infinite alternate;
}
body::after {
  width: 40vw;
  height: 40vw;
  max-width: 500px;
  max-height: 500px;
  background: var(--blob-2);
  bottom: -10%;
  left: -8%;
  animation: blobDrift2 30s ease-in-out infinite alternate;
}

#app {
  position: relative;
  z-index: 1;
  min-height: 100vh;
}

/* ========== TYPOGRAPHY ========== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.2;
  color: var(--text-primary);
}

h1 { font-size: clamp(1.75rem, 4vw, 2.5rem); }
h2 { font-size: clamp(1.35rem, 3vw, 1.85rem); }
h3 { font-size: clamp(1.1rem, 2.5vw, 1.4rem); }
h4 { font-size: 1.1rem; }

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

.text-gradient {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.text-sm { font-size: 0.875rem; }
.text-xs { font-size: 0.75rem; }
.text-muted { color: var(--text-muted); }
.text-center { text-align: center; }

/* ========== GLASS PANEL ========== */
.glass {
  background: var(--gradient-surface);
  backdrop-filter: blur(24px) saturate(140%);
  -webkit-backdrop-filter: blur(24px) saturate(140%);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  transition: border-color var(--transition-base),
              box-shadow var(--transition-base),
              transform var(--transition-base);
}
.glass:hover {
  border-color: var(--border-medium);
}
.glass-elevated {
  background: var(--bg-elevated);
  backdrop-filter: blur(32px) saturate(160%);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-lg);
}

/* ========== BUTTONS ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 0.65rem 1.5rem;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
  user-select: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-primary);
  color: #fff;
  box-shadow: 0 4px 15px var(--primary-glow);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 25px var(--primary-glow), var(--shadow-glow);
}
.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-medium);
}
.btn-secondary:hover {
  background: var(--bg-surface-hover);
  border-color: var(--border-strong);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  padding: 0.5rem 1rem;
}
.btn-ghost:hover {
  background: var(--bg-surface);
  color: var(--text-primary);
}

.btn-sm {
  padding: 0.4rem 1rem;
  font-size: 0.8rem;
}

.btn-lg {
  padding: 0.85rem 2rem;
  font-size: 1rem;
}

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: var(--radius-md);
  font-size: 1.2rem;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none !important;
}

/* Shimmer effect on primary buttons */
.btn-primary::after {
  content: '';
  position: absolute;
  top: 0; left: -100%;
  width: 100%; height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.15), transparent);
  transition: left 0.5s ease;
}
.btn-primary:hover::after {
  left: 100%;
}

/* ========== FORM ELEMENTS ========== */
input[type="text"],
input[type="email"],
input[type="number"],
textarea,
select {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: var(--font-body);
  font-size: 0.95rem;
  color: var(--text-primary);
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  outline: none;
  transition: all var(--transition-base);
  resize: vertical;
}

input:focus, textarea:focus, select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-glow);
  background: var(--bg-surface-hover);
}

input::placeholder, textarea::placeholder {
  color: var(--text-muted);
}

select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' fill='rgba(255,255,255,0.5)'%3E%3Cpath d='M1 1l5 5 5-5'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
}

.form-group {
  margin-bottom: var(--space-lg);
}

/* ========== CUSTOM RANGE SLIDER ========== */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  background: var(--border-medium);
  border-radius: var(--radius-full);
  outline: none;
  transition: background var(--transition-base);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  box-shadow: 0 0 12px var(--primary-glow);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  border: 3px solid rgba(255,255,255,0.2);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
  box-shadow: 0 0 20px var(--primary-glow);
}

input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  box-shadow: 0 0 12px var(--primary-glow);
  border: 3px solid rgba(255,255,255,0.2);
}

/* ========== BADGES & CHIPS ========== */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 0.2rem 0.65rem;
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: var(--radius-full);
  border: 1px solid;
}

.badge-primary {
  color: var(--primary-light);
  border-color: var(--primary-glow);
  background: rgba(168, 85, 247, 0.1);
}
.badge-secondary {
  color: var(--secondary-light);
  border-color: var(--secondary-glow);
  background: rgba(6, 182, 212, 0.1);
}
.badge-success {
  color: var(--success);
  border-color: var(--success-glow);
  background: rgba(16, 185, 129, 0.1);
}
.badge-warning {
  color: var(--warning);
  border-color: var(--accent-glow);
  background: rgba(245, 158, 11, 0.1);
}
.badge-error {
  color: var(--error);
  border-color: var(--error-glow);
  background: rgba(244, 63, 94, 0.1);
}

/* ========== ONBOARDING OVERLAY ========== */
.onboarding-overlay {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-base);
  padding: var(--space-md);
  animation: fadeIn 0.5s var(--ease-out);
}

.onboarding-card {
  width: 100%;
  max-width: 640px;
  max-height: 90vh;
  overflow-y: auto;
  padding: var(--space-2xl);
  position: relative;
}

.onboarding-header {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.onboarding-logo {
  font-size: 2.5rem;
  margin-bottom: var(--space-sm);
}

.onboarding-title {
  margin-bottom: var(--space-sm);
}

.onboarding-subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Phase indicator */
.phase-indicator {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  margin-bottom: var(--space-2xl);
}

.phase-dot {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  border: 2px solid var(--border-medium);
  color: var(--text-muted);
  background: var(--bg-surface);
  transition: all var(--transition-base);
  position: relative;
  z-index: 2;
}

.phase-dot.active {
  border-color: var(--primary);
  color: #fff;
  background: var(--primary);
  box-shadow: 0 0 20px var(--primary-glow);
}

.phase-dot.completed {
  border-color: var(--success);
  color: #fff;
  background: var(--success);
}

.phase-line {
  width: 60px;
  height: 2px;
  background: var(--border-medium);
  transition: background var(--transition-base);
}

.phase-line.completed {
  background: var(--success);
}

/* Phase content */
.phase-content {
  animation: slideUp 0.4s var(--ease-out);
}

.phase-content[hidden] {
  display: none;
}

/* Slider groups (psychometric) */
.slider-group {
  margin-bottom: var(--space-xl);
}

.slider-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
}

.slider-label {
  font-size: 0.9rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.slider-value {
  font-size: 1.4rem;
  font-weight: 700;
  min-width: 2rem;
  text-align: center;
}

.slider-emoji-scale {
  display: flex;
  justify-content: space-between;
  padding: 0 2px;
  margin-top: var(--space-xs);
  font-size: 0.7rem;
  color: var(--text-muted);
}

/* Onboarding navigation */
.onboarding-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
}

/* ========== SYNTHESIS OVERLAY ========== */
.synthesis-overlay {
  position: fixed;
  inset: 0;
  z-index: 1100;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--bg-base);
  gap: var(--space-xl);
}

.synthesis-orb {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: var(--gradient-primary);
  position: relative;
  animation: orbPulse 2s ease-in-out infinite;
}

.synthesis-orb::before,
.synthesis-orb::after {
  content: '';
  position: absolute;
  inset: -15px;
  border-radius: 50%;
  border: 2px solid var(--primary-glow);
  animation: orbRing 3s linear infinite;
}

.synthesis-orb::after {
  inset: -30px;
  animation-delay: -1s;
  animation-duration: 4s;
  border-color: var(--secondary-glow);
}

.synthesis-text {
  font-family: var(--font-heading);
  font-size: 1.2rem;
  color: var(--text-secondary);
  animation: textPulse 2s ease-in-out infinite;
}

.synthesis-steps {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  align-items: center;
}

.synthesis-step {
  font-size: 0.85rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  transition: all var(--transition-base);
}

.synthesis-step.active {
  color: var(--primary-light);
}

.synthesis-step.done {
  color: var(--success);
}

/* ========== MAIN APP LAYOUT ========== */
.app-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-md);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) 0;
  margin-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.app-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.app-brand-icon {
  font-size: 1.6rem;
}

.app-brand-name {
  font-family: var(--font-heading);
  font-size: 1.3rem;
  font-weight: 700;
}

.app-header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.xp-pill {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.35rem 0.85rem;
  background: var(--accent-glow);
  border: 1px solid rgba(245, 158, 11, 0.3);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
}

.level-pill {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.35rem 0.85rem;
  background: var(--primary-glow);
  border: 1px solid rgba(168, 85, 247, 0.3);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--primary-light);
}

/* ========== TAB NAVIGATION ========== */
.tab-nav {
  display: flex;
  gap: var(--space-xs);
  padding: var(--space-xs);
  background: var(--bg-surface);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
  margin-bottom: var(--space-xl);
  overflow-x: auto;
  flex-shrink: 0;
}

.tab-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 0.7rem 1rem;
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
  user-select: none;
}

.tab-btn:hover {
  color: var(--text-secondary);
  background: var(--bg-surface-hover);
}

.tab-btn.active {
  color: var(--text-primary);
  background: var(--bg-elevated);
  border: 1px solid var(--border-medium);
  box-shadow: var(--shadow-sm);
  font-weight: 600;
}

.tab-btn .tab-icon {
  font-size: 1.1rem;
}

.tab-content {
  flex: 1;
  animation: fadeIn 0.3s var(--ease-out);
}

.tab-content[hidden] {
  display: none;
}

/* ========== DASHBOARD ========== */
.dashboard-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
}

.dashboard-welcome {
  grid-column: 1 / -1;
  padding: var(--space-2xl);
  text-align: center;
}

.dashboard-welcome h2 {
  margin-bottom: var(--space-sm);
}

.dashboard-welcome .coach-message {
  color: var(--text-secondary);
  font-size: 1.05rem;
  font-style: italic;
  max-width: 600px;
  margin: 0 auto;
}

.dashboard-card {
  padding: var(--space-xl);
}

.dashboard-card h3 {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  font-size: 1rem;
}

/* Progress rings */
.progress-rings {
  display: flex;
  justify-content: center;
  gap: var(--space-2xl);
  flex-wrap: wrap;
}

.progress-ring-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
}

.progress-ring {
  width: 90px;
  height: 90px;
  position: relative;
}

.progress-ring svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.progress-ring circle {
  fill: none;
  stroke-width: 5;
  stroke-linecap: round;
}

.progress-ring .ring-bg {
  stroke: var(--border-subtle);
}

.progress-ring .ring-fill {
  stroke: var(--primary);
  transition: stroke-dashoffset 1s var(--ease-out);
}

.progress-ring .ring-value {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  font-weight: 700;
  font-family: var(--font-heading);
}

.progress-ring-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
}

/* Next reviews */
.review-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.review-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  transition: all var(--transition-fast);
  cursor: pointer;
}

.review-item:hover {
  background: var(--bg-surface-hover);
  border-color: var(--border-medium);
}

.review-item-left {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.review-subject-icon {
  font-size: 1.3rem;
}

.review-topic {
  font-size: 0.9rem;
  font-weight: 500;
}

.review-subject {
  font-size: 0.75rem;
  color: var(--text-muted);
}

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

/* ========== LESSONS VIEW ========== */
.lesson-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.topic-selector {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.topic-chip {
  padding: 0.5rem 1.2rem;
  font-size: 0.85rem;
  font-weight: 500;
  border-radius: var(--radius-full);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-base);
}

.topic-chip:hover {
  border-color: var(--border-medium);
  color: var(--text-primary);
}

.topic-chip.active {
  background: var(--primary-glow);
  border-color: var(--primary);
  color: var(--primary-light);
}

.lesson-generator {
  padding: var(--space-2xl);
  text-align: center;
  margin-bottom: var(--space-xl);
}

.lesson-generator p {
  margin-bottom: var(--space-lg);
}

.lesson-input-row {
  display: flex;
  gap: var(--space-md);
  max-width: 600px;
  margin: 0 auto var(--space-lg);
}

.lesson-input-row input {
  flex: 1;
}

.lesson-elements {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

/* ========== LESSON ELEMENT (Shared) ========== */
.lesson-element {
  padding: var(--space-xl);
  border-left: 3px solid var(--border-medium);
  position: relative;
  overflow: hidden;
}

.lesson-element::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--gradient-primary);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.lesson-element:hover::before {
  opacity: 1;
}

.element-header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.element-icon {
  font-size: 1.8rem;
  flex-shrink: 0;
}

.element-meta {
  flex: 1;
}

.element-type {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.element-title {
  font-size: 1.15rem;
  font-weight: 600;
}

/* ========== COMPONENT: Teaser ========== */
.lesson-element[data-type="teaser"] {
  border-left-color: var(--secondary);
  background: linear-gradient(135deg, rgba(6, 182, 212, 0.05), transparent);
}

.teaser-text {
  font-size: 1.1rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.teaser-highlight {
  background: linear-gradient(135deg, var(--secondary-glow), transparent);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--secondary-light);
  font-weight: 600;
}

/* ========== COMPONENT: Thought Experiment ========== */
.lesson-element[data-type="thought_experiment"] {
  border-left-color: var(--accent);
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.05), transparent);
}

.thought-question {
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: var(--space-lg);
  padding: var(--space-lg);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
}

.thought-reveal-btn {
  margin-bottom: var(--space-md);
}

.thought-answer {
  padding: var(--space-lg);
  background: rgba(245, 158, 11, 0.06);
  border-radius: var(--radius-md);
  border: 1px solid rgba(245, 158, 11, 0.15);
  line-height: 1.7;
  animation: slideUp 0.3s var(--ease-out);
}

.thought-answer[hidden] { display: none; }

/* ========== COMPONENT: Interactive Slider ========== */
.lesson-element[data-type="interactive_slider"] {
  border-left-color: var(--primary);
  background: linear-gradient(135deg, rgba(168, 85, 247, 0.05), transparent);
}

.formula-display {
  text-align: center;
  padding: var(--space-lg);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
  font-family: var(--font-heading);
}

.formula-main {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--primary-light);
  margin-bottom: var(--space-sm);
}

.formula-result {
  font-size: 2rem;
  font-weight: 800;
  color: var(--text-primary);
}

.formula-result .unit {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: 400;
}

.slider-controls {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.slider-control {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.slider-control-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
}

.slider-var-name {
  font-weight: 600;
  color: var(--primary-light);
}

.slider-var-value {
  font-weight: 700;
  color: var(--text-primary);
  font-family: var(--font-heading);
}

/* ========== COMPONENT: Flashcard ========== */
.lesson-element[data-type="flashcard"] {
  border-left-color: var(--success);
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.05), transparent);
}

.flashcard-container {
  perspective: 1000px;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  min-height: 180px;
  transition: transform 0.6s var(--ease-out);
  transform-style: preserve-3d;
}

.flashcard-container.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl);
  border-radius: var(--radius-md);
  text-align: center;
}

.flashcard-front {
  background: var(--bg-surface);
  border: 1px solid var(--border-medium);
}

.flashcard-back {
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.2);
  transform: rotateY(180deg);
}

.flashcard-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
}

.flashcard-text {
  font-size: 1.15rem;
  font-weight: 500;
  line-height: 1.6;
}

.flashcard-hint {
  margin-top: var(--space-md);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ========== COMPONENT: Error Detective ========== */
.lesson-element[data-type="error_detective"] {
  border-left-color: var(--error);
  background: linear-gradient(135deg, rgba(244, 63, 94, 0.05), transparent);
}

.detective-instructions {
  margin-bottom: var(--space-lg);
  color: var(--text-secondary);
}

.detective-content {
  padding: var(--space-lg);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  font-size: 1.05rem;
  line-height: 2;
  border: 1px solid var(--border-subtle);
}

.detective-segment {
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 3px;
  transition: all var(--transition-fast);
}

.detective-segment:hover {
  background: rgba(244, 63, 94, 0.1);
}

.detective-segment.selected {
  background: rgba(244, 63, 94, 0.15);
  outline: 2px solid var(--error);
  outline-offset: 1px;
}

.detective-segment.correct-pick {
  background: rgba(16, 185, 129, 0.15);
  outline-color: var(--success);
}

.detective-segment.wrong-pick {
  background: rgba(244, 63, 94, 0.2);
  text-decoration: line-through;
}

.detective-feedback {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  animation: slideUp 0.3s var(--ease-out);
}

.detective-feedback.success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.2);
  color: var(--success);
}

.detective-feedback.error {
  background: rgba(244, 63, 94, 0.1);
  border: 1px solid rgba(244, 63, 94, 0.2);
  color: var(--error);
}

/* ========== COMPONENT: Active Recall ========== */
.lesson-element[data-type="active_recall"] {
  border-left-color: #8b5cf6;
  background: linear-gradient(135deg, rgba(139, 92, 246, 0.05), transparent);
}

.recall-prompt {
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: var(--space-lg);
  padding: var(--space-lg);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
}

.recall-input-area {
  display: flex;
  gap: var(--space-md);
}

.recall-input-area textarea {
  flex: 1;
  min-height: 80px;
}

.recall-feedback {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  line-height: 1.6;
  animation: slideUp 0.3s var(--ease-out);
}

/* ========== COMPONENT: Sorting Puzzle ========== */
.lesson-element[data-type="sorting_puzzle"] {
  border-left-color: #f97316;
  background: linear-gradient(135deg, rgba(249, 115, 22, 0.05), transparent);
}

.sorting-instructions {
  margin-bottom: var(--space-lg);
  color: var(--text-secondary);
}

.sorting-items {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.sorting-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  cursor: grab;
  transition: all var(--transition-fast);
  user-select: none;
}

.sorting-item:active {
  cursor: grabbing;
}

.sorting-item:hover {
  background: var(--bg-surface-hover);
  border-color: var(--border-medium);
}

.sorting-item.dragging {
  opacity: 0.5;
  background: var(--primary-glow);
  border-color: var(--primary);
  transform: scale(0.98);
}

.sorting-item.drag-over {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary-glow);
}

.sorting-item.correct {
  border-color: var(--success);
  background: rgba(16, 185, 129, 0.08);
}

.sorting-item.incorrect {
  border-color: var(--error);
  background: rgba(244, 63, 94, 0.08);
}

.sorting-handle {
  color: var(--text-muted);
  font-size: 1.1rem;
}

.sorting-number {
  font-weight: 700;
  color: var(--text-muted);
  min-width: 24px;
  font-size: 0.85rem;
}

.sorting-text {
  flex: 1;
  font-size: 0.95rem;
}

/* ========== COMPONENT: Sandbox Simulation ========== */
.lesson-element[data-type="sandbox_simulation"] {
  border-left-color: #14b8a6;
  background: linear-gradient(135deg, rgba(20, 184, 166, 0.05), transparent);
}

.sandbox-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
}

.sandbox-controls {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.sandbox-visualization {
  padding: var(--space-lg);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  min-height: 200px;
}

.sandbox-bar {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.sandbox-bar-label {
  font-size: 0.8rem;
  min-width: 80px;
  color: var(--text-secondary);
}

.sandbox-bar-track {
  flex: 1;
  height: 20px;
  background: var(--border-subtle);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.sandbox-bar-fill {
  height: 100%;
  border-radius: var(--radius-full);
  transition: width 0.5s var(--ease-out), background 0.5s ease;
  background: var(--success);
}

.sandbox-bar-fill.warning {
  background: var(--warning);
}

.sandbox-bar-fill.danger {
  background: var(--error);
}

.sandbox-status {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  text-align: center;
  font-weight: 600;
  font-size: 0.9rem;
}

.sandbox-status.balanced {
  background: rgba(16, 185, 129, 0.1);
  color: var(--success);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

.sandbox-status.imbalanced {
  background: rgba(244, 63, 94, 0.1);
  color: var(--error);
  border: 1px solid rgba(244, 63, 94, 0.2);
}

/* ========== COMPONENT: Quest Card ========== */
.lesson-element[data-type="quest_card"] {
  border-left-color: #eab308;
  background: linear-gradient(135deg, rgba(234, 179, 8, 0.06), transparent);
  border: 1px solid rgba(234, 179, 8, 0.15);
}

.quest-story {
  font-size: 1.05rem;
  line-height: 1.8;
  margin-bottom: var(--space-lg);
  padding: var(--space-lg);
  background: rgba(234, 179, 8, 0.04);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--accent);
  font-style: italic;
}

.quest-objective {
  font-weight: 600;
  margin-bottom: var(--space-lg);
  color: var(--text-primary);
}

.quest-input-area {
  display: flex;
  gap: var(--space-md);
}

.quest-input-area input {
  flex: 1;
}

.quest-result {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  animation: slideUp 0.3s var(--ease-out);
}

.quest-result.success {
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.2);
  color: var(--success);
}

.quest-result.failure {
  background: rgba(244, 63, 94, 0.1);
  border: 1px solid rgba(244, 63, 94, 0.2);
  color: var(--error);
}

/* ========== COMPONENT: Retention Checkpoint ========== */
.lesson-element[data-type="retention_checkpoint"] {
  border-left-color: #6366f1;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.06), transparent);
}

.retention-question {
  font-size: 1.05rem;
  margin-bottom: var(--space-xl);
  text-align: center;
}

.retention-scale {
  display: flex;
  justify-content: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.retention-btn {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-medium);
  background: var(--bg-surface);
  color: var(--text-secondary);
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.retention-btn:hover {
  border-color: var(--primary);
  color: var(--primary-light);
  transform: translateY(-2px);
}

.retention-btn.selected {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 0 15px var(--primary-glow);
  transform: scale(1.1);
}

.retention-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  max-width: 500px;
  margin: 0 auto;
}

.retention-feedback {
  margin-top: var(--space-lg);
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-secondary);
  animation: fadeIn 0.3s var(--ease-out);
}

/* ========== KNOWLEDGE TABLE ========== */
.knowledge-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.knowledge-table-container {
  overflow-x: auto;
}

.knowledge-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
}

.knowledge-table th,
.knowledge-table td {
  padding: var(--space-md) var(--space-lg);
  text-align: left;
  border-bottom: 1px solid var(--border-subtle);
}

.knowledge-table th {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  background: var(--bg-surface);
  position: sticky;
  top: 0;
}

.knowledge-table th:first-child {
  border-radius: var(--radius-md) 0 0 0;
}
.knowledge-table th:last-child {
  border-radius: 0 var(--radius-md) 0 0;
}

.knowledge-table td {
  font-size: 0.9rem;
}

.knowledge-table tr:hover td {
  background: var(--bg-surface);
}

.confidence-bar {
  width: 80px;
  height: 6px;
  background: var(--border-subtle);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.confidence-fill {
  height: 100%;
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
}

.trend-up { color: var(--success); }
.trend-down { color: var(--error); }
.trend-stable { color: var(--text-muted); }

/* ========== COACH CHAT ========== */
.coach-container {
  display: flex;
  flex-direction: column;
  height: calc(100vh - 250px);
  min-height: 400px;
}

.coach-header {
  padding: var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-md);
  border-bottom: 1px solid var(--border-subtle);
}

.coach-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
}

.coach-info h3 { font-size: 1rem; margin-bottom: 2px; }
.coach-info p { font-size: 0.8rem; color: var(--text-muted); }

.coach-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.chat-message {
  max-width: 80%;
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-lg);
  line-height: 1.6;
  font-size: 0.95rem;
  animation: slideUp 0.3s var(--ease-out);
}

.chat-message.coach {
  align-self: flex-start;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-bottom-left-radius: var(--space-xs);
}

.chat-message.user {
  align-self: flex-end;
  background: var(--primary-glow);
  border: 1px solid rgba(168, 85, 247, 0.2);
  border-bottom-right-radius: var(--space-xs);
}

.chat-message.typing {
  display: flex;
  gap: 4px;
  padding: var(--space-md) var(--space-lg);
}

.typing-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-muted);
  animation: typingBounce 1.4s ease-in-out infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

.coach-input-area {
  padding: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  gap: var(--space-md);
}

.coach-input-area input {
  flex: 1;
}

/* ========== DOCS TAB ========== */
.docs-container {
  max-width: 800px;
  margin: 0 auto;
}

.docs-header {
  margin-bottom: var(--space-2xl);
}

.doc-section {
  margin-bottom: var(--space-2xl);
  padding: var(--space-xl);
}

.doc-section h3 {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.doc-section h3 .doc-icon {
  font-size: 1.5rem;
}

.doc-section p {
  margin-bottom: var(--space-md);
}

.doc-json {
  background: rgba(0,0,0,0.3);
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  overflow-x: auto;
  font-family: 'Courier New', monospace;
  font-size: 0.82rem;
  line-height: 1.6;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

.doc-json .key { color: var(--primary-light); }
.doc-json .string { color: var(--success); }
.doc-json .number { color: var(--accent); }
.doc-json .boolean { color: var(--secondary-light); }

/* ========== SETTINGS MODAL ========== */
.settings-modal {
  position: fixed;
  inset: 0;
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(8px);
  animation: fadeIn 0.2s var(--ease-out);
}

.settings-modal[hidden] { display: none; }

.settings-card {
  width: 100%;
  max-width: 480px;
  padding: var(--space-2xl);
  margin: var(--space-md);
}

.settings-card h2 {
  margin-bottom: var(--space-xl);
}

/* ========== EMPTY STATES ========== */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-3xl);
  text-align: center;
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: var(--space-lg);
  opacity: 0.5;
}

.empty-state h3 {
  margin-bottom: var(--space-sm);
}

.empty-state p {
  max-width: 400px;
}

/* ========== TOAST NOTIFICATIONS ========== */
.toast-container {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.toast {
  padding: var(--space-md) var(--space-lg);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  animation: slideInRight 0.3s var(--ease-spring);
  backdrop-filter: blur(20px);
  border: 1px solid;
  min-width: 250px;
}

.toast-success {
  background: rgba(16, 185, 129, 0.15);
  border-color: rgba(16, 185, 129, 0.3);
  color: var(--success);
}

.toast-error {
  background: rgba(244, 63, 94, 0.15);
  border-color: rgba(244, 63, 94, 0.3);
  color: var(--error);
}

.toast-info {
  background: rgba(6, 182, 212, 0.15);
  border-color: rgba(6, 182, 212, 0.3);
  color: var(--secondary-light);
}

.toast-xp {
  background: rgba(245, 158, 11, 0.15);
  border-color: rgba(245, 158, 11, 0.3);
  color: var(--accent);
  font-weight: 700;
}

/* ========== LOADING SPINNER ========== */
.spinner {
  width: 24px;
  height: 24px;
  border: 3px solid var(--border-medium);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

.spinner-lg {
  width: 40px;
  height: 40px;
  border-width: 4px;
}

/* ========== KEYFRAME ANIMATIONS ========== */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

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

@keyframes slideUp {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-12px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(30px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes blobDrift1 {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(-50px, 30px) scale(1.1); }
  100% { transform: translate(20px, -20px) scale(0.95); }
}

@keyframes blobDrift2 {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(40px, -40px) scale(1.15); }
  100% { transform: translate(-30px, 20px) scale(0.9); }
}

@keyframes orbPulse {
  0%, 100% { transform: scale(1); box-shadow: 0 0 40px var(--primary-glow); }
  50% { transform: scale(1.08); box-shadow: 0 0 80px var(--primary-glow); }
}

@keyframes orbRing {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

@keyframes textPulse {
  0%, 100% { opacity: 0.7; }
  50% { opacity: 1; }
}

@keyframes typingBounce {
  0%, 60%, 100% { transform: translateY(0); }
  30% { transform: translateY(-6px); }
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

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

@keyframes confetti {
  0% { transform: translateY(0) rotate(0deg); opacity: 1; }
  100% { transform: translateY(-100px) rotate(720deg); opacity: 0; }
}

@keyframes levelUp {
  0% { transform: scale(1); }
  50% { transform: scale(1.2); }
  100% { transform: scale(1); }
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
  .dashboard-grid {
    grid-template-columns: 1fr;
  }

  .sandbox-layout {
    grid-template-columns: 1fr;
  }

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

  .tab-btn .tab-icon {
    font-size: 1.3rem;
  }

  .tab-btn {
    padding: 0.7rem;
  }

  .onboarding-card {
    padding: var(--space-lg);
  }

  .app-header {
    flex-wrap: wrap;
    gap: var(--space-sm);
  }

  .lesson-input-row {
    flex-direction: column;
  }

  .quest-input-area,
  .recall-input-area {
    flex-direction: column;
  }

  .chat-message {
    max-width: 90%;
  }

  .coach-container {
    height: calc(100vh - 200px);
  }

  .retention-scale {
    gap: var(--space-xs);
  }

  .retention-btn {
    width: 38px;
    height: 38px;
    font-size: 0.85rem;
  }
}

@media (max-width: 480px) {
  html { font-size: 14px; }

  .app-container {
    padding: var(--space-sm);
  }

  .progress-rings {
    gap: var(--space-lg);
  }

  .phase-line {
    width: 30px;
  }

  .onboarding-card {
    padding: var(--space-md);
  }

  .lesson-element {
    padding: var(--space-lg);
  }

  .flashcard-inner {
    min-height: 140px;
  }
}

/* ========== PRINT ========== */
@media print {
  body::before, body::after { display: none; }
  .tab-nav, .app-header-actions, .coach-input-area { display: none; }
  .glass, .glass-elevated { backdrop-filter: none; border: 1px solid #ccc; }
  body { background: #fff; color: #000; }
}

/* ========== DYNAMIC PERSONALIZED LAYOUT STYLES ========== */
/* Sidebar Layout Override */
.app-container.layout-sidebar {
  display: grid;
  grid-template-columns: 240px 1fr;
  grid-template-rows: auto 1fr;
  grid-template-areas: 
    "header header"
    "nav content";
  min-height: 100vh;
  max-width: 1450px;
  margin: 0 auto;
  padding: 0 var(--space-md);
}

.app-container.layout-sidebar .app-header {
  grid-area: header;
  border-bottom: 1px solid var(--border-subtle);
  padding: var(--space-md) 0;
  width: 100%;
}

.app-container.layout-sidebar .tab-nav {
  grid-area: nav;
  flex-direction: column;
  align-items: stretch;
  justify-content: flex-start;
  border-bottom: none;
  border-right: 1px solid var(--border-subtle);
  padding: var(--space-md) var(--space-sm) var(--space-md) 0;
  gap: var(--space-xs);
  height: auto;
}

.app-container.layout-sidebar .tab-nav .tab-btn {
  border-bottom: none;
  border-left: 3px solid transparent;
  padding: var(--space-sm) var(--space-md);
  text-align: left;
  border-radius: var(--radius-sm);
  width: 100%;
}

.app-container.layout-sidebar .tab-nav .tab-btn.active {
  border-left-color: var(--primary);
  background: var(--bg-surface);
  border-bottom: none;
}

.app-container.layout-sidebar .tab-content {
  grid-area: content;
  padding: var(--space-lg) 0 var(--space-2xl) var(--space-lg);
}

/* Compact layout (ZEN / Minimalist) */
.app-container.layout-minimal-zen {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--space-sm);
}

.app-container.layout-minimal-zen .dashboard-grid {
  grid-template-columns: 1fr !important; /* Single column dashboard */
  gap: var(--space-lg);
}

.app-container.layout-minimal-zen .lesson-elements {
  max-width: var(--lesson-max-width, 680px);
  margin: 0 auto;
}

/* Gaming HUD style modifications */
.app-container.layout-gaming-hud .glass,
.app-container.layout-gaming-hud .glass-elevated {
  border-width: var(--border-width, 2px) !important;
  box-shadow: 0 0 15px var(--primary-glow) !important;
}

.app-container.layout-gaming-hud .tab-btn.active {
  box-shadow: 0 0 10px var(--primary-glow);
  text-shadow: 0 0 5px var(--primary-glow);
}

/* Custom spacing overrides */
.app-container.density-spacious {
  --space-md: 1.5rem;
  --space-lg: 2rem;
  --space-xl: 3rem;
}

.app-container.density-dense {
  --space-sm: 0.25rem;
  --space-md: 0.65rem;
  --space-lg: 1rem;
  --space-xl: 1.5rem;
}