/* ============================================
   DMV Passing - Dark Gaming Theme
   ============================================ */

/* Google Fonts - loaded via <link> in HTML for non-blocking load */

/* ============================================
   CSS Custom Properties
   ============================================ */
:root {
  /* Colors */
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-card: #1e293b;
  --bg-card-hover: #263548;
  --bg-glass: rgba(30, 41, 59, 0.85);
  --bg-input: #0f172a;

  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent-blue: #3b82f6;
  --accent-cyan: #06b6d4;
  --accent-purple: #8b5cf6;
  --accent-green: #10b981;
  --accent-red: #ef4444;
  --accent-amber: #f59e0b;
  --accent-pink: #ec4899;

  --border-color: rgba(148, 163, 184, 0.12);
  --border-glow: rgba(59, 130, 246, 0.5);

  --gradient-hero: linear-gradient(135deg, #0a0e17 0%, #1a1a3e 50%, #0a0e17 100%);
  --gradient-card: linear-gradient(145deg, #1e293b, #162032);
  --gradient-accent: linear-gradient(135deg, #3b82f6, #8b5cf6);
  --gradient-success: linear-gradient(135deg, #10b981, #06b6d4);
  --gradient-fire: linear-gradient(135deg, #f59e0b, #ef4444);

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.3);
  --shadow-glow-green: 0 0 20px rgba(16, 185, 129, 0.3);
  --shadow-glow-red: 0 0 20px rgba(239, 68, 68, 0.3);

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;

  /* Z-index */
  --z-dropdown: 100;
  --z-nav: 200;
  --z-modal: 300;
  --z-toast: 400;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: 'DM Sans', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(ellipse at 20% 20%, rgba(59, 130, 246, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 80%, rgba(139, 92, 246, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(6, 182, 212, 0.04) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-blue);
}

img {
  max-width: 100%;
  display: block;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  line-height: 1.2;
}

/* ============================================
   Navigation
   ============================================ */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: rgba(10, 14, 23, 0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  z-index: var(--z-nav);
  display: flex;
  align-items: center;
  padding: 0 var(--space-lg);
}

.nav-inner {
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.6rem;
  color: var(--text-primary);
  text-decoration: none;
}

.nav-logo svg {
  width: 38px;
  height: 38px;
}

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

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: rgba(59, 130, 246, 0.1);
}

.nav-links a.active {
  color: var(--accent-cyan);
}

.nav-hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: var(--space-sm);
}

/* Mobile Nav */
@media (max-width: 768px) {
  .nav-hamburger {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(10, 14, 23, 0.98);
    backdrop-filter: blur(20px);
    padding: var(--space-md);
    gap: var(--space-xs);
    border-bottom: 1px solid var(--border-color);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    width: 100%;
    padding: var(--space-md);
  }
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
  position: relative;
  z-index: 1;
  padding-top: 80px; /* below fixed nav (64px) + small gap */
  min-height: 100vh;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.section {
  padding: var(--space-3xl) 0;
}

.section.section--compact {
  padding: var(--space-xl) 0;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  text-align: center;
  padding: var(--space-3xl) 0 var(--space-2xl);
  position: relative;
  overflow: hidden;
}

.hero.hero--compact {
  padding: var(--space-2xl) 0 var(--space-xl);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at center, rgba(59, 130, 246, 0.1) 0%, transparent 50%);
  animation: heroGlow 8s ease-in-out infinite;
}

@keyframes heroGlow {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(-5%, 5%); }
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  background: rgba(59, 130, 246, 0.1);
  border: 1px solid rgba(59, 130, 246, 0.2);
  color: var(--accent-cyan);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: var(--space-lg);
}

.hero h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 900;
  margin-bottom: var(--space-md);
}

.hero h1 .gradient-text {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-xl);
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: var(--space-2xl);
  margin-top: var(--space-xl);
}

.hero-stat {
  text-align: center;
}

.hero-stat .stat-number {
  font-family: 'Outfit', sans-serif;
  font-size: 2rem;
  font-weight: 800;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-stat .stat-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

/* ============================================
   Action Cards (Homepage)
   ============================================ */
.action-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-lg);
  padding: var(--space-xl) 0;
}

.section--compact .action-cards {
  padding: var(--space-md) 0;
}

.action-cards.grid-2x2 {
  grid-template-columns: repeat(2, 1fr);
}

/* How It Works: 3 modules in a row */
.action-cards.how-it-works-cards {
  grid-template-columns: repeat(3, 1fr);
}

@media (max-width: 900px) {
  .action-cards.how-it-works-cards {
    grid-template-columns: 1fr;
  }
}

.action-card {
  position: relative;
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  text-decoration: none;
  color: var(--text-primary);
  transition: all var(--transition-normal);
  overflow: hidden;
  cursor: pointer;
}

.action-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-accent);
  opacity: 0;
  transition: opacity var(--transition-normal);
}

.action-card:hover {
  transform: translateY(-4px);
  border-color: rgba(59, 130, 246, 0.3);
  box-shadow: var(--shadow-glow);
}

.action-card:hover::before {
  opacity: 1;
}

/* Home page card — structured layout */
.action-card.home-card {
  display: flex;
  flex-direction: column;
  padding: var(--space-lg) var(--space-xl) var(--space-lg);
}

.action-card.home-card .card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
}

.action-card.home-card .card-body {
  flex: 1;
}

.action-card.home-card .card-footer {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
  margin-top: var(--space-lg);
  padding-top: var(--space-md);
  border-top: 1px solid var(--border-color);
}

.card-tag {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 20px;
  letter-spacing: 0.3px;
}

.card-tag.blue {
  background: rgba(59, 130, 246, 0.12);
  color: var(--accent-blue);
}

.card-tag.purple {
  background: rgba(139, 92, 246, 0.12);
  color: var(--accent-purple);
}

.card-tag.green {
  background: rgba(16, 185, 129, 0.12);
  color: var(--accent-green);
}

.card-tag.cyan {
  background: rgba(6, 182, 212, 0.12);
  color: var(--accent-cyan);
}

.action-card-icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
  margin-bottom: var(--space-md);
}

.home-card .action-card-icon {
  margin-bottom: 0;
}

.action-card-icon.blue {
  background: rgba(59, 130, 246, 0.15);
  color: var(--accent-blue);
}

.action-card-icon.purple {
  background: rgba(139, 92, 246, 0.15);
  color: var(--accent-purple);
}

.action-card-icon.cyan {
  background: rgba(6, 182, 212, 0.15);
  color: var(--accent-cyan);
}

.action-card-icon.green {
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-green);
}

.action-card h3 {
  font-size: 1.25rem;
  margin-bottom: var(--space-xs);
}

.action-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.55;
}

.action-card .card-arrow {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(59, 130, 246, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-blue);
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.action-card:hover .card-arrow {
  background: var(--accent-blue);
  color: white;
  transform: translateX(4px);
}

/* Wrong to Review card: arrow at bottom-right */
#wrongReviewCard .card-arrow {
  position: absolute;
  bottom: var(--space-md);
  right: var(--space-md);
}

#wrongReviewCard:hover .card-arrow {
  transform: translateX(4px);
}

/* ============================================
   State Grid
   ============================================ */
.state-grid-section {
  padding: var(--space-xl) 0;
}

.search-bar {
  position: relative;
  max-width: 500px;
  margin: 0 auto var(--space-xl);
}

.search-bar input {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  padding-left: 48px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-family: 'DM Sans', sans-serif;
  font-size: 1rem;
  outline: none;
  transition: all var(--transition-fast);
}

.search-bar input:focus {
  border-color: var(--accent-blue);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.search-bar input::placeholder {
  color: var(--text-muted);
}

.search-bar .search-icon {
  position: absolute;
  left: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

.state-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: var(--space-md);
}

.state-card {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  text-align: center;
  text-decoration: none;
  color: var(--text-primary);
  transition: all var(--transition-normal);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.state-card:hover {
  transform: translateY(-3px);
  border-color: rgba(6, 182, 212, 0.3);
  box-shadow: 0 0 15px rgba(6, 182, 212, 0.2);
}

.state-card .state-abbr {
  font-family: 'Outfit', sans-serif;
  font-size: 1.8rem;
  font-weight: 800;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: var(--space-xs);
}

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

.state-card .state-count {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

/* ============================================
   Rule Detail Page
   ============================================ */
.rule-detail-header {
  text-align: center;
  padding: var(--space-3xl) 0 var(--space-xl);
}

.rule-detail-header .state-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.2);
  color: var(--accent-cyan);
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-full);
  font-weight: 600;
  margin-bottom: var(--space-md);
}

.rule-detail-header h1 {
  font-size: 2.5rem;
  margin-bottom: var(--space-md);
}

.rule-sections {
  display: grid;
  gap: var(--space-xl);
  max-width: 900px;
  margin: 0 auto;
}

.rule-section {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
}

.rule-section h2 {
  font-size: 1.4rem;
  margin-bottom: var(--space-md);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.rule-section p,
.rule-section li {
  color: var(--text-secondary);
  line-height: 1.8;
}

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

.rule-section ul li {
  padding: var(--space-sm) 0;
  padding-left: var(--space-lg);
  position: relative;
}

.rule-section ul li::before {
  content: '>';
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
  font-weight: 700;
}

/* Calculator pages (car-loan, car-insurance) */
.rule-section.calculator-section {
  max-width: 920px;
  margin: var(--space-3xl) auto;
  padding: var(--space-2xl) var(--space-xl);
}

.calculator-title {
  text-align: center;
  font-size: 2rem;
  margin-bottom: var(--space-md);
}

.calculator-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
  margin-bottom: var(--space-2xl);
}

.calc-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-lg);
  align-items: flex-end;
}

.calc-field {
  flex: 1;
  min-width: 180px;
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

.calc-field label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: var(--space-sm);
}

.calc-select,
.calc-input {
  width: 100%;
  box-sizing: border-box;
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 1.05rem;
}

.calc-select {
  padding-right: var(--space-2xl);
}

.calc-select:focus,
.calc-input:focus {
  outline: none;
  border-color: var(--accent-blue);
}

.calc-select:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  background: var(--bg-secondary);
}

.calc-field:has(.calc-select:disabled) label {
  color: var(--text-muted);
}

.calc-actions {
  display: flex;
  justify-content: center;
  margin-top: var(--space-lg);
}
.calculator-result {
  padding: var(--space-2xl);
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.2);
  border-radius: var(--radius-lg);
}
.calculator-result.hidden {
  display: none;
}
.calculator-result h3 {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-sm);
}
.calculator-result .result-value {
  font-family: 'Outfit', sans-serif;
  font-size: 2.75rem;
  font-weight: 800;
  color: var(--accent-green);
  margin-bottom: var(--space-lg);
}
.result-details {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
}
.result-row {
  padding: var(--space-xs) 0;
}
.result-disclaimer {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0;
}

.pdf-link-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  background: var(--gradient-accent);
  color: white;
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-md);
}

.pdf-link-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
  color: white;
}

/* ============================================
   Quiz / Practice Page
   ============================================ */
.quiz-container {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--space-xl) 0 var(--space-3xl);
}

/* Challenge: extra padding for breathing room */
#challengeArea .quiz-container {
  padding-bottom: 80px;
}

/* State Selector */
.state-selector {
  padding: var(--space-3xl) 0;
  text-align: center;
}

.state-selector h2 {
  font-size: 2rem;
  margin-bottom: var(--space-sm);
}

.state-selector p {
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
}

.state-select-desc {
  color: var(--text-secondary);
  text-align: center;
  max-width: 480px;
  margin: 0 auto var(--space-md);
  font-size: 0.95rem;
  line-height: 1.5;
}

.category-select-desc {
  color: var(--text-secondary);
  text-align: center;
  max-width: 560px;
  margin: 0 auto var(--space-lg);
  font-size: 0.95rem;
  line-height: 1.6;
}

.state-selector-compact {
  padding: var(--space-xl) 0;
}

.state-selector-compact .search-bar {
  margin-bottom: var(--space-lg);
}

#stateSelector.state-selector-compact {
  padding-top: var(--space-lg);
}

.state-select-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: var(--space-sm);
  max-width: 800px;
  margin: 0 auto;
}

.state-select-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: var(--space-md);
  color: var(--text-primary);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.state-select-btn:hover {
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.1);
  transform: scale(1.03);
}

.state-select-btn .abbr {
  display: block;
  font-size: 1.2rem;
  color: var(--accent-cyan);
}

/* Quiz Header */
.quiz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
  padding: var(--space-md);
  background: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}


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

.quiz-progress-bar {
  width: 200px;
  height: 8px;
  background: var(--bg-primary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.quiz-progress-fill {
  height: 100%;
  background: var(--gradient-accent);
  border-radius: var(--radius-full);
  transition: width var(--transition-normal);
}

.quiz-progress-text {
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.quiz-score {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  color: var(--accent-green);
}

/* Question Card */
#questionCard {
  margin-top: var(--space-md);
}
.question-card {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--space-xl) var(--space-2xl);
  margin-bottom: var(--space-xl);
  animation: slideIn 0.4s ease;
}

#challengeQuestionCard {
  margin-top: var(--space-md);
}
#challengeQuestionCard .question-card {
  padding: var(--space-xl) var(--space-2xl);
}
#challengeQuestionCard .timer-bar {
  margin-top: 0;
  margin-bottom: var(--space-lg);
}

.question-number {
  font-family: 'Outfit', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--space-md);
}

.question-text {
  font-size: 1.2rem;
  font-weight: 500;
  line-height: 1.65;
  margin-bottom: var(--space-xl);
}

.options-list {
  display: grid;
  gap: var(--space-md);
}

/* Challenge: options scroll within card when they overflow — prevents option D from being cut off */
#challengeQuestionCard .options-list {
  max-height: min(480px, max(280px, calc(100vh - 400px)));
  overflow-y: auto;
  overflow-x: hidden;
  padding-right: 4px;
}

#challengeQuestionCard .options-list::-webkit-scrollbar {
  width: 6px;
}

#challengeQuestionCard .options-list::-webkit-scrollbar-track {
  background: var(--bg-primary);
  border-radius: var(--radius-full);
}

#challengeQuestionCard .options-list::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: var(--radius-full);
}

#challengeQuestionCard .options-list::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

.option-btn {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  width: 100%;
  padding: var(--space-lg) var(--space-xl);
  min-height: 56px;
  background: var(--bg-input);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: 'DM Sans', sans-serif;
  font-size: 1rem;
  line-height: 1.4;
  text-align: left;
  cursor: pointer;
  transition: all var(--transition-fast);
}

#challengeQuestionCard .option-btn {
  padding: var(--space-md) var(--space-lg);
  min-height: 48px;
}

.option-btn > span:last-child {
  flex: 1;
  padding-top: 4px;
}

.option-btn:hover:not(.disabled) {
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.08);
  transform: translateX(4px);
}

.option-btn .option-letter {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(148, 163, 184, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--text-secondary);
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.option-btn:hover:not(.disabled) .option-letter {
  background: rgba(59, 130, 246, 0.2);
  color: var(--accent-blue);
}

.option-btn.correct {
  border-color: var(--accent-green);
  background: rgba(16, 185, 129, 0.25);
  box-shadow: 0 0 20px rgba(16, 185, 129, 0.4);
  animation: correctPulse 0.6s ease;
}

.option-btn.correct .option-letter {
  background: var(--accent-green);
  color: white;
  box-shadow: 0 0 12px rgba(16, 185, 129, 0.6);
}

.option-btn.wrong {
  border-color: var(--accent-red);
  background: rgba(239, 68, 68, 0.1);
  animation: wrongShake 0.5s ease;
}

.option-btn.wrong .option-letter {
  background: var(--accent-red);
  color: white;
}

.option-btn.disabled {
  cursor: not-allowed;
  opacity: 0.7;
}

.option-btn.show-correct {
  border-color: var(--accent-green);
  background: rgba(16, 185, 129, 0.05);
}

/* Explanation */
#challengeExplanation {
  margin-top: var(--space-xl);
  margin-bottom: var(--space-xl);
}

#challengeQuestionCard #challengeExplanation {
  margin-top: var(--space-lg);
  margin-bottom: 0;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-color);
}

.explanation {
  margin-top: var(--space-md);
  padding: var(--space-lg);
  background: rgba(59, 130, 246, 0.08);
  border-left: 3px solid var(--accent-blue);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  animation: fadeIn 0.3s ease;
}

#challengeQuestionCard .explanation {
  margin-top: 0;
  padding: var(--space-lg) var(--space-xl);
  border-left-width: 4px;
}

.explanation-title {
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  color: var(--accent-blue);
  margin-bottom: var(--space-md);
}

.explanation-text {
  color: var(--text-secondary);
  line-height: 1.65;
}


/* Next Button */
.next-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  width: 100%;
  max-width: 300px;
  margin: var(--space-lg) auto 0;
  padding: var(--space-md) var(--space-xl);
  background: var(--gradient-accent);
  border: none;
  border-radius: var(--radius-full);
  color: white;
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-md);
}

.next-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

/* ============================================
   Challenge Mode
   ============================================ */

/* Timer Bar */
.timer-bar {
  width: 100%;
  height: 6px;
  background: var(--bg-primary);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-lg);
  overflow: hidden;
}

.timer-bar-fill {
  height: 100%;
  background: var(--gradient-accent);
  border-radius: var(--radius-full);
  transition: width 0.1s linear;
}

.timer-bar-fill.warning {
  background: var(--accent-amber);
}

.timer-bar-fill.danger {
  background: var(--accent-red);
}

/* Streak & Multiplier */
.challenge-stats {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.streak-badge {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: var(--radius-full);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  color: var(--accent-amber);
  font-size: 0.9rem;
}

.streak-badge.on-fire {
  background: rgba(239, 68, 68, 0.15);
  border-color: rgba(239, 68, 68, 0.3);
  color: var(--accent-red);
  animation: firePulse 1s ease infinite;
}

.multiplier-badge {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-md);
  background: rgba(139, 92, 246, 0.1);
  border: 1px solid rgba(139, 92, 246, 0.2);
  border-radius: var(--radius-full);
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  color: var(--accent-purple);
  font-size: 0.9rem;
}

.points-display {
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--accent-cyan);
}

.points-popup {
  position: fixed;
  pointer-events: none;
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.5rem;
  color: var(--accent-green);
  animation: pointsFly 1s ease forwards;
  z-index: var(--z-toast);
}

/* Ready Screen */
.ready-screen {
  position: relative;
  text-align: center;
  padding: var(--space-3xl);
  min-height: calc(100vh - 64px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.back-btn-top-left {
  position: absolute;
  left: 0;
  top: 0;
  margin: 0;
}

.ready-screen h2 {
  font-size: 2.5rem;
  margin-bottom: var(--space-lg);
}

.countdown-number {
  font-family: 'Outfit', sans-serif;
  font-size: 8rem;
  font-weight: 900;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: countdownPulse 1s ease infinite;
}

.start-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-lg) var(--space-2xl);
  background: var(--gradient-accent);
  border: none;
  border-radius: var(--radius-full);
  color: white;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 1.2rem;
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-glow);
}

.start-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 0 30px rgba(59, 130, 246, 0.5);
}

/* Results Screen */
.results-screen {
  text-align: center;
  padding: var(--space-2xl) 0;
  animation: fadeIn 0.5s ease;
}

.results-card {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  max-width: 600px;
  margin: 0 auto;
}

.results-stars {
  margin-bottom: var(--space-lg);
}

.results-stars .star {
  font-size: 3rem;
  margin: 0 var(--space-xs);
  display: inline-block;
  animation: starPop 0.3s ease both;
  color: var(--text-muted);
}

.results-stars .star.earned {
  color: var(--accent-amber);
  text-shadow: 0 0 20px rgba(245, 158, 11, 0.5);
}

.results-stars .star:nth-child(1) { animation-delay: 0.2s; }
.results-stars .star:nth-child(2) { animation-delay: 0.4s; }
.results-stars .star:nth-child(3) { animation-delay: 0.6s; }

.results-score {
  font-family: 'Outfit', sans-serif;
  font-size: 4rem;
  font-weight: 900;
  margin-bottom: var(--space-sm);
}

.results-score.perfect {
  background: var(--gradient-success);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.results-score.good {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.results-score.ok {
  color: var(--accent-amber);
}

.results-score.poor {
  color: var(--accent-red);
}

.results-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.results-title.pass {
  color: var(--accent-green);
}

.results-title.near {
  color: var(--accent-amber);
}

.results-title.fail {
  color: var(--accent-red);
}

.results-label {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
  line-height: 1.5;
}

.results-details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.results-detail {
  padding: var(--space-md);
  background: var(--bg-primary);
  border-radius: var(--radius-md);
}

.results-detail .detail-value {
  font-family: 'Outfit', sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
}

.results-detail .detail-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: var(--space-xs);
}

.results-xp {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  background: rgba(139, 92, 246, 0.1);
  border: 1px solid rgba(139, 92, 246, 0.2);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-xl);
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  color: var(--accent-purple);
  font-size: 1.1rem;
}

.results-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  max-width: 400px;
  margin: 0 auto;
}

.results-actions .btn-primary,
.results-actions .btn-secondary,
.results-actions a.btn-secondary {
  min-width: 0;
  justify-content: center;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  min-height: 48px;
  white-space: nowrap;
  background: var(--gradient-accent);
  border: none;
  border-radius: var(--radius-full);
  color: white;
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  min-height: 48px;
  white-space: nowrap;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.btn-secondary:hover {
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.1);
}

/* ============================================
   Ad Slots（隐藏由 JS setupAdUnfilledHide 处理，不依赖 CSS）
   ============================================ */

.ad-slot-wrapper {
  position: relative;
  padding-top: 20px; /* space for label above the box */
  margin: var(--space-xl) 0;
  width: 100%;
}

.ad-slot {
  width: 100%;
  min-height: 120px;
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
  display: block;
}

.ad-label {
  position: absolute;
  top: 0;
  right: 0;
  font-size: 0.7rem;
  color: #999;
  text-transform: lowercase;
  letter-spacing: 0.02em;
}

/* ============================================
   Sidebar Ads / Calculator Nav (scrolls with page)
   Left: 2 calculator navs. Right: 1 ad.
   ============================================ */
.page-layout {
  display: grid;
  grid-template-columns: 320px 1fr 320px;
  gap: 0;
  max-width: none;
  padding-top: 80px; /* below fixed nav (64px) + small gap */
}

.page-layout .main-content {
  margin: 0;
  min-width: 0;
}

.corner-ad {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
  pointer-events: auto;
  align-self: start; /* don't stretch; height = content */
}

.corner-ad.left {
  width: 320px;
  padding-left: 12px;
  overflow: visible;
}

.corner-ad.right {
  width: 320px;
  padding-right: 12px;
  overflow: visible;
}


.corner-ad-inner {
  width: 100%;
  min-height: 320px;
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
  display: block;
  position: relative;
}

.corner-ad-inner.corner-ad-only {
  min-height: 400px; /* fallback until JS sets to match left */
}

.corner-ad-wrapper {
  margin-top: 22px;
}

/* Advertisement label in separate row above ad container */
.corner-ad-label-row {
  display: block;
  min-height: 20px;
  margin-bottom: 8px;
  text-align: right;
}

.corner-ad-wrapper .corner-ad-label-row .ad-label {
  position: static;
  display: inline-block;
  font-size: 0.7rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Inline ad container: 保持可见高度供 AdSense 识别（过小会导致不填充，120px 利于匹配更多尺寸） */
.ad-slot-inline {
  min-height: 120px !important;
}
.ad-slot-inline.ad-slot-loading {
  min-height: 120px !important;
}
/* When ad loading: minimal gap to next element */
.ad-slot-inline.ad-slot-loading + .quiz-header,
.ad-slot-inline.ad-slot-loading + #questionCard,
.ad-slot-inline.ad-slot-loading + #challengeQuestionCard {
  margin-top: 2px;
}

.ad-slot-inline .ad-slot-wrapper {
  margin: var(--space-md) 0;
  padding-top: 20px;
  padding-bottom: var(--space-md);
}
.ad-slot-inline .ad-slot-wrapper.ad-slot-loading {
  padding-top: 20px;
  padding-bottom: var(--space-md);
  margin: var(--space-md) 0;
}
.ad-slot-inline .ad-slot-wrapper.ad-slot-loading .ad-slot {
  min-height: 120px !important;
}
.ad-slot-inline .ad-slot-wrapper.ad-slot-loading .ad-slot ins.adsbygoogle {
  min-height: 120px !important;
  display: block;
}
/* When ad loaded */
.ad-slot-inline .ad-slot-wrapper.ad-slot-loaded .ad-slot {
  min-height: 70px;
  max-height: none;
  max-width: 100%;
  margin-left: 0;
  margin-right: 0;
}
.ad-slot-inline .ad-slot-wrapper.ad-slot-loaded {
  padding-top: 20px;
  padding-bottom: var(--space-md);
  margin: var(--space-md) 0;
}

.corner-ad-slot {
  width: 100%;
  min-height: 90px;
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
  display: block;
}

.corner-ad-nav {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-xl);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  text-decoration: none;
  text-align: left;
  transition: all var(--transition-fast);
}
.corner-ad-nav:hover {
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent-blue);
}
.corner-ad-nav-img {
  width: 100%;
  height: 120px;
  object-fit: cover;
  border-radius: var(--radius-sm);
  background: var(--bg-input);
}
.corner-ad-nav-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  margin: 0;
  color: inherit;
}
.corner-ad-nav-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin: 0;
  line-height: 1.5;
}
.corner-ad-nav:hover .corner-ad-nav-desc {
  color: inherit;
  opacity: 0.9;
}

.corner-ad-close {
  position: absolute;
  top: 4px;
  right: 6px;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.75rem;
  padding: 2px;
  line-height: 1;
  opacity: 0.5;
  transition: opacity 0.2s;
}

.corner-ad-close:hover {
  opacity: 1;
}

/* On narrow screens: single column, hide sidebars. 1200px 以下才隐藏，1366/1280 等常见笔电可见侧边广告 */
@media (max-width: 1200px) {
  .page-layout {
    display: block;
  }
  .page-layout .corner-ad {
    display: none;
  }
  .page-layout .main-content {
    margin: 0;
  }
}

@media (min-width: 1201px) {
  .page-layout {
    display: grid;
  }
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--space-2xl) 0;
  margin-top: var(--space-xl); /* reduced from 3xl (64px) to xl (32px) */
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: var(--space-xl);
}

.footer-left {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  max-width: 320px;
}

.footer-logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-primary);
  text-decoration: none;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  transition: opacity var(--transition-fast);
}

.footer-logo:hover {
  opacity: 0.9;
}

.footer-logo svg {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
  color: var(--accent-cyan);
}

.footer-logo .logo-gradient {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.footer-text {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin: 0;
}

.footer-blocks {
  display: flex;
  gap: var(--space-2xl);
  flex-wrap: wrap;
  margin-left: 0;
  max-width: 560px;
}

.footer-block {
  min-width: 140px;
}

.footer-block-title {
  font-family: 'Outfit', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.footer-block-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-block-links li {
  margin-bottom: var(--space-xs);
}

.footer-block-links a {
  color: var(--accent-blue);
  font-size: 0.85rem;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer-block-links a:hover {
  color: var(--accent-cyan);
}

/* ============================================
   Level & XP Bar
   ============================================ */
.user-level {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-xl);
}

.level-badge {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--gradient-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Outfit', sans-serif;
  font-weight: 900;
  font-size: 1.2rem;
  color: white;
  flex-shrink: 0;
}

.level-info {
  flex: 1;
}

.level-title {
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: var(--space-xs);
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.title-icon {
  font-size: 1.2rem;
}

.next-title-hint {
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-muted);
  margin-left: auto;
}

.xp-bar {
  width: 100%;
  height: 8px;
  background: var(--bg-primary);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.xp-bar-fill {
  height: 100%;
  background: var(--gradient-accent);
  border-radius: var(--radius-full);
  transition: width var(--transition-slow);
}

.xp-text {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.xp-learned-count {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 4px;
}

.xp-learned-label {
  color: var(--accent-cyan);
}

.results-level-bar {
  margin-top: var(--space-lg);
}

.btn-reset-progress {
  display: inline-block;
  margin-top: var(--space-sm);
  padding: var(--space-xs) var(--space-sm);
  font-size: 0.8rem;
  color: var(--text-muted);
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}
.btn-reset-progress:hover {
  color: var(--accent-red);
  border-color: var(--accent-red);
}

.xp-bar-fill.xp-animate {
  transition: width 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Level up / Title upgrade - centered popup */
.level-up-overlay,
.title-upgrade-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 99999;
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: auto;
}

.level-up-overlay.visible,
.title-upgrade-overlay.visible {
  opacity: 1;
}

.level-up-card,
.title-upgrade-card {
  position: relative;
  background: var(--gradient-card);
  border: 2px solid var(--accent-amber);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl) var(--space-3xl);
  text-align: center;
  max-width: 320px;
  margin: auto;
  box-shadow: 0 25px 50px -12px rgba(0,0,0,0.5);
  transform: translate(-50%, -50%) scale(0.85);
  opacity: 0;
  animation: popIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

.level-up-overlay .level-up-card,
.title-upgrade-overlay .title-upgrade-card {
  position: fixed;
  left: 50%;
  top: 50%;
}

@keyframes popIn {
  to {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
}

.level-up-badge {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--gradient-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Outfit', sans-serif;
  font-weight: 900;
  font-size: 2rem;
  color: white;
  margin: 0 auto var(--space-md);
  border: 4px solid;
}

.level-up-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.8rem;
  font-weight: 800;
  margin-bottom: var(--space-xs);
}

.level-up-subtitle {
  font-size: 1.2rem;
  font-weight: 600;
}

.title-upgrade-icon {
  font-size: 3rem;
  margin-bottom: var(--space-sm);
}

.title-upgrade-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: var(--space-xs);
}

.title-upgrade-sub {
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ============================================
   Confetti
   ============================================ */
.confetti-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: var(--z-toast);
  overflow: hidden;
}

.confetti {
  position: absolute;
  width: 10px;
  height: 10px;
  border-radius: 2px;
  animation: confettiFall 3s ease-out forwards;
}

/* ============================================
   Page Title Section
   ============================================ */
.page-header {
  text-align: center;
  padding: var(--space-3xl) 0 var(--space-xl);
}

.page-header h1 {
  font-size: 2.5rem;
  margin-bottom: var(--space-sm);
}

.page-header p {
  color: var(--text-secondary);
  font-size: 1.1rem;
}

/* ============================================
   Section Title
   ============================================ */
.section-title {
  font-size: 1.8rem;
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section--compact .section-title {
  margin-bottom: var(--space-md);
}

/* ============================================
   Back Button
   ============================================ */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-weight: 500;
  padding: var(--space-sm) 0;
  margin-bottom: var(--space-lg);
  transition: color var(--transition-fast);
  cursor: pointer;
  background: none;
  border: none;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.95rem;
}

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

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

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

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

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

@keyframes correctPulse {
  0% { transform: scale(1); box-shadow: 0 0 20px rgba(16, 185, 129, 0.4); }
  40% { transform: scale(1.08); box-shadow: 0 0 35px rgba(16, 185, 129, 0.7); }
  70% { transform: scale(1.04); }
  100% { transform: scale(1); box-shadow: 0 0 20px rgba(16, 185, 129, 0.4); }
}

@keyframes wrongShake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-8px); }
  40% { transform: translateX(8px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

@keyframes countdownPulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.1); opacity: 0.8; }
}

@keyframes firePulse {
  0%, 100% { box-shadow: 0 0 0 rgba(239, 68, 68, 0); }
  50% { box-shadow: 0 0 15px rgba(239, 68, 68, 0.3); }
}

@keyframes pointsFly {
  0% {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
  100% {
    opacity: 0;
    transform: translateY(-80px) scale(1.5);
  }
}

@keyframes starPop {
  0% {
    opacity: 0;
    transform: scale(0) rotate(-30deg);
  }
  60% {
    transform: scale(1.3) rotate(5deg);
  }
  100% {
    opacity: 1;
    transform: scale(1) rotate(0);
  }
}

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

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero-stats {
    gap: var(--space-lg);
  }

  .hero-stat .stat-number {
    font-size: 1.5rem;
  }

  .action-cards {
    grid-template-columns: 1fr;
  }

  .action-cards.grid-2x2 {
    grid-template-columns: 1fr;
  }

  .state-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  }

  .state-select-grid {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  }

  .results-details {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }

  .quiz-header {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .quiz-progress-bar {
    width: 100%;
  }

  .rule-detail-header h1 {
    font-size: 1.8rem;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
    align-items: center;
  }

  .footer-left {
    align-items: center;
  }

  .footer-blocks {
    margin-left: 0;
    justify-content: center;
  }

  .footer-block {
    text-align: center;
  }

  .challenge-stats {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-md);
  }

  .section {
    padding: var(--space-xl) 0;
  }

  .question-text {
    font-size: 1.05rem;
  }

  .option-btn {
    padding: var(--space-md);
    font-size: 0.9rem;
  }
}

/* ============================================
   Scrollbar
   ============================================ */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--bg-card);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--bg-card-hover);
}

/* ============================================
   Toast Notification
   ============================================ */
.toast {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  padding: var(--space-md) var(--space-xl);
  background: var(--bg-glass);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-weight: 500;
  z-index: var(--z-toast);
  animation: fadeInUp 0.3s ease;
  box-shadow: var(--shadow-lg);
}

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

.toast.error {
  border-color: rgba(239, 68, 68, 0.3);
}

/* ============================================
   Strike / Combo Animation
   ============================================ */
.strike-overlay {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: var(--z-toast);
  pointer-events: none;
  text-align: center;
  animation: strikeAppear 0.8s ease forwards;
}

.strike-text {
  font-family: 'Outfit', sans-serif;
  font-weight: 900;
  font-size: 3rem;
  text-transform: uppercase;
  letter-spacing: 4px;
  -webkit-text-stroke: 1px rgba(255,255,255,0.2);
}

.strike-text.streak-1 {
  font-size: 2.25rem;
  color: var(--accent-green);
  text-shadow: 0 0 30px rgba(16, 185, 129, 0.6), 0 0 60px rgba(16, 185, 129, 0.3);
}

.strike-text.streak-2 {
  font-size: 2.5rem;
  color: var(--accent-blue);
  text-shadow: 0 0 30px rgba(59, 130, 246, 0.5);
}

.strike-text.streak-3 {
  font-size: 3rem;
  color: var(--accent-cyan);
  text-shadow: 0 0 40px rgba(6, 182, 212, 0.6);
}

.strike-text.streak-5 {
  font-size: 3.5rem;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 20px rgba(139, 92, 246, 0.6));
}

.strike-text.streak-7 {
  font-size: 4rem;
  background: var(--gradient-fire);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 25px rgba(239, 68, 68, 0.7));
}

.strike-text.streak-10 {
  font-size: 4.5rem;
  background: linear-gradient(135deg, #f59e0b, #ef4444, #ec4899, #8b5cf6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  filter: drop-shadow(0 0 30px rgba(236, 72, 153, 0.7));
}

.strike-sub {
  font-family: 'Outfit', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-top: var(--space-xs);
  letter-spacing: 2px;
}

@keyframes strikeAppear {
  0% {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.3);
  }
  30% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1.15);
  }
  50% {
    transform: translate(-50%, -50%) scale(1);
  }
  80% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
  100% {
    opacity: 0;
    transform: translate(-50%, -60%) scale(0.9);
  }
}

/* ============================================
   Resume Prompt
   ============================================ */
.resume-prompt {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--space-3xl) 0;
  animation: fadeIn 0.3s ease;
}

.resume-card {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  max-width: 480px;
  width: 100%;
  text-align: center;
}

.resume-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--space-lg);
  background: rgba(59, 130, 246, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-blue);
}

.resume-icon svg {
  width: 32px;
  height: 32px;
}

.resume-card h2 {
  margin-bottom: var(--space-sm);
}

.resume-card > p {
  color: var(--text-secondary);
  margin-bottom: var(--space-xl);
}

.resume-details {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
}

.resume-detail {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  text-align: center;
}

.resume-label {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
}

.resume-value {
  display: block;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  color: var(--accent-cyan);
}

.resume-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
}

/* ============================================
   Flashcards
   ============================================ */
.flashcard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
  gap: var(--space-md);
}

.flashcard-progress-text {
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  color: var(--text-secondary);
}

.flashcard-filter {
  display: flex;
  gap: var(--space-xs);
}

.filter-btn {
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-family: 'DM Sans', sans-serif;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  border-color: var(--accent-blue);
  color: var(--text-primary);
}

.filter-btn.active {
  background: rgba(59, 130, 246, 0.15);
  border-color: var(--accent-blue);
  color: var(--accent-blue);
}

/* 3D Flashcard */
.flashcard-container {
  perspective: 1200px;
  max-width: 640px;
  margin: 0 auto var(--space-xl);
  min-height: 380px;
}

.flashcard {
  position: relative;
  width: 100%;
  min-height: 380px;
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.flashcard-front,
.flashcard-back {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  min-height: 380px;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.flashcard-front {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
}

.flashcard-back {
  background: linear-gradient(145deg, #162032, #1a2a42);
  border: 1px solid rgba(6, 182, 212, 0.2);
  transform: rotateY(180deg);
}

.fc-mastered-badge {
  position: absolute;
  top: var(--space-md);
  right: var(--space-md);
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-green);
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
}

.fc-question-number {
  font-family: 'Outfit', sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: var(--space-md);
}

.fc-question-text {
  font-size: 1.2rem;
  font-weight: 500;
  line-height: 1.6;
  margin-bottom: var(--space-lg);
}

.fc-options-preview {
  display: grid;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.fc-option {
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-input);
  border-radius: var(--radius-sm);
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.fc-hint {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-style: italic;
}

.fc-back-layout {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.fc-back-question {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-color);
}

.fc-answer-section {
  margin-bottom: var(--space-md);
}

.fc-answer-label {
  font-family: 'Outfit', sans-serif;
  font-size: 0.75rem;
  color: var(--accent-cyan);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: var(--space-xs);
}

.fc-answer {
  font-family: 'Outfit', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent-green);
  line-height: 1.4;
}

.fc-divider {
  height: 1px;
  background: var(--border-color);
  margin-bottom: var(--space-md);
}

.fc-explanation-section {
  flex: 1;
}

.fc-explanation-label {
  font-family: 'Outfit', sans-serif;
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: var(--space-xs);
}

.fc-explanation {
  color: var(--text-secondary);
  line-height: 1.65;
  font-size: 0.95rem;
}

/* Flashcard Controls */
.flashcard-controls {
  display: flex;
  justify-content: center;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.fc-btn {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition-fast);
  background: var(--bg-card);
  color: var(--text-primary);
}

.fc-btn svg {
  width: 18px;
  height: 18px;
}

.fc-btn.fc-review:hover {
  border-color: var(--accent-red);
  background: rgba(239, 68, 68, 0.1);
  color: var(--accent-red);
}

.fc-btn.fc-flip:hover {
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent-blue);
}

.fc-btn.fc-mastered:hover {
  border-color: var(--accent-green);
  background: rgba(16, 185, 129, 0.1);
  color: var(--accent-green);
}

.flashcard-nav {
  display: flex;
  justify-content: space-between;
  max-width: 640px;
  margin: 0 auto var(--space-xl);
}

.fc-nav-btn {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: none;
  border: none;
  color: var(--text-secondary);
  font-family: 'DM Sans', sans-serif;
  font-size: 0.9rem;
  cursor: pointer;
  transition: color var(--transition-fast);
}

.fc-nav-btn:hover:not(:disabled) {
  color: var(--accent-cyan);
}

.fc-nav-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.empty-state {
  text-align: center;
  padding: var(--space-3xl);
  color: var(--text-secondary);
}

.empty-state p {
  margin-bottom: var(--space-lg);
}

/* ============================================
   Study Guide
   ============================================ */
.guide-header {
  margin-bottom: var(--space-xl);
}

.guide-header h2 {
  font-size: 1.8rem;
  margin-bottom: var(--space-sm);
}

.guide-sections {
  display: grid;
  gap: var(--space-md);
  max-width: 900px;
}

.guide-section {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.guide-section.learned {
  border-color: rgba(16, 185, 129, 0.2);
}

.guide-section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-lg) var(--space-xl);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.guide-section-header:hover {
  background: rgba(59, 130, 246, 0.05);
}

/* Practice category selector (Study-like topic cards) */
.practice-category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--space-md);
  max-width: 800px;
  margin: 0 auto;
}

.practice-topic-card {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-lg) var(--space-xl);
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.practice-topic-card:hover {
  border-color: rgba(59, 130, 246, 0.4);
  background: rgba(59, 130, 246, 0.05);
  transform: translateX(4px);
}

.practice-topic-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  background: rgba(148, 163, 184, 0.1);
  color: var(--text-secondary);
}

.practice-topic-icon svg {
  width: 20px;
  height: 20px;
}

.practice-topic-title {
  flex: 1;
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1rem;
}

.practice-topic-count {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.practice-topic-done {
  position: absolute;
  top: 10px;
  right: 10px;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.9), rgba(6, 182, 212, 0.9));
  border-radius: 50%;
  box-shadow: 0 2px 12px rgba(16, 185, 129, 0.4), inset 0 1px 0 rgba(255,255,255,0.25);
  border: 1px solid rgba(255,255,255,0.2);
  color: white;
}

.practice-topic-done svg {
  width: 14px;
  height: 14px;
  color: white;
  filter: drop-shadow(0 1px 1px rgba(0,0,0,0.2));
}

.guide-section-title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 1.1rem;
}

.guide-question-count {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--text-muted);
  background: var(--bg-primary);
  padding: 2px 10px;
  border-radius: var(--radius-full);
}

.guide-learned-tag {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-green);
  background: rgba(16, 185, 129, 0.1);
  padding: 2px 10px;
  border-radius: var(--radius-full);
}

.guide-chevron {
  transition: transform var(--transition-normal);
  color: var(--text-muted);
  flex-shrink: 0;
}

.guide-chevron.rotated {
  transform: rotate(180deg);
}

.guide-section-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  padding: 0 var(--space-xl);
}

.guide-section-content.open {
  max-height: 8000px;
  padding: 0 var(--space-xl) var(--space-xl);
}

/* Pagination for Study Guide topics */
.guide-pagination {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  margin: var(--space-lg) 0;
  padding: var(--space-md) 0;
  border-top: 1px solid var(--border-color);
}

.guide-pagination-info {
  font-size: 0.9rem;
  color: var(--text-muted);
}

.guide-pagination-btns {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.guide-page-btn {
  padding: var(--space-sm) var(--space-md);
  font-size: 0.9rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.guide-page-btn:hover:not(:disabled) {
  background: rgba(59, 130, 246, 0.1);
  border-color: var(--accent-blue);
}

.guide-page-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.guide-page-btn.active {
  background: rgba(59, 130, 246, 0.2);
  border-color: var(--accent-blue);
}

.guide-page-numbers {
  font-size: 0.9rem;
  color: var(--text-secondary);
  padding: 0 var(--space-sm);
}

.guide-topic-desc {
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  font-size: 0.95rem;
}

.guide-rules-list {
  list-style: none;
  padding: 0;
}

.guide-rules-list li {
  padding: var(--space-sm) 0;
  padding-left: var(--space-lg);
  position: relative;
  color: var(--text-secondary);
  line-height: 1.6;
}

.guide-rules-list li::before {
  content: '>';
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
  font-weight: 700;
}

.guide-overview {
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  background: rgba(59, 130, 246, 0.05);
  border-radius: var(--radius-md);
}

.guide-overview h4 {
  color: var(--accent-blue);
  margin-bottom: var(--space-sm);
}

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

.guide-questions {
  display: grid;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.guide-qa {
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
}

.guide-q {
  display: flex;
  gap: var(--space-sm);
  font-weight: 500;
  margin-bottom: var(--space-md);
  line-height: 1.5;
}

.guide-q-num {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: rgba(6, 182, 212, 0.15);
  color: var(--accent-cyan);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 0.8rem;
}

.guide-a {
  color: var(--accent-green);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.guide-a-label {
  color: var(--text-muted);
  font-weight: 400;
  margin-right: var(--space-xs);
}

.guide-exp {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

.guide-learn-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  color: var(--text-primary);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.guide-learn-btn:hover {
  border-color: var(--accent-green);
  background: rgba(16, 185, 129, 0.1);
}

.guide-learn-btn.learned {
  border-color: var(--accent-green);
  background: rgba(16, 185, 129, 0.15);
  color: var(--accent-green);
}

/* Flashcard responsive */
@media (max-width: 768px) {
  .flashcard-container {
    min-height: 320px;
  }

  .flashcard {
    min-height: 320px;
  }

  .flashcard-front,
  .flashcard-back {
    min-height: 320px;
    padding: var(--space-lg);
  }

  .fc-question-text {
    font-size: 1.05rem;
  }

  .flashcard-controls {
    flex-wrap: wrap;
  }

  .fc-btn {
    font-size: 0.8rem;
    padding: var(--space-sm) var(--space-md);
  }

  .flashcard-filter {
    flex-wrap: wrap;
  }
}

/* ============================================
   Challenge / Practice Review Overlay (Wrong Questions Popup)
   ============================================ */
.review-overlay {
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--space-2xl);
  overflow-y: auto;
  animation: fadeIn 0.2s ease;
}

/* Lock body scroll when review overlay is open */
body.review-overlay-open {
  overflow: hidden;
}

.review-overlay.hidden {
  display: none !important;
}

.review-modal {
  background: var(--gradient-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  max-width: 640px;
  width: 100%;
  max-height: calc(100vh - 96px);
  overflow-y: auto;
  margin: auto;
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.05);
}

.review-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-color);
}

.review-header h3 {
  margin: 0;
  font-size: 1.25rem;
}

.btn-sm {
  padding: var(--space-xs) var(--space-md);
  font-size: 0.85rem;
}

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

.review-item {
  padding: var(--space-md);
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--border-color);
}

.review-item.correct {
  border-left-color: var(--accent-green);
}

.review-item.wrong {
  border-left-color: var(--accent-red);
}

.review-q-num {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
}

.review-q-text {
  font-weight: 500;
  margin-bottom: var(--space-sm);
  line-height: 1.4;
}

.review-choices {
  font-size: 0.9rem;
  margin-bottom: var(--space-sm);
}

.review-choice {
  margin-bottom: var(--space-xs);
}

.review-choice.user-wrong {
  color: var(--accent-red);
}

.review-choice.correct-answer {
  color: var(--accent-green);
}

.review-label {
  font-weight: 600;
  margin-right: var(--space-xs);
}

.review-explanation {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* Wrong Review - grouped by topic */
.wrong-review-toc {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm) var(--space-md);
  padding: var(--space-md) 0;
  margin-bottom: var(--space-lg);
  border-bottom: 1px solid var(--border-color);
}

.wrong-review-toc-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-right: var(--space-sm);
}

.wrong-review-toc-link {
  font-size: 0.9rem;
  color: var(--accent-blue);
  padding: 4px 12px;
  background: rgba(59, 130, 246, 0.1);
  border: none;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.wrong-review-toc-link:hover {
  background: rgba(59, 130, 246, 0.2);
  color: var(--accent-cyan);
}

.wrong-review-group {
  margin-bottom: var(--space-md);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.wrong-review-group:last-child {
  margin-bottom: 0;
}

.wrong-review-group-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  cursor: pointer;
  background: var(--bg-card);
  transition: background var(--transition-fast);
}

.wrong-review-group-header:hover {
  background: var(--bg-card-hover);
}

.wrong-review-group-chevron {
  width: 16px;
  height: 16px;
  border-right: 2px solid var(--text-muted);
  border-bottom: 2px solid var(--text-muted);
  transform: rotate(-45deg);
  transition: transform var(--transition-fast);
}

.wrong-review-group--expanded .wrong-review-group-chevron {
  transform: rotate(45deg);
}

.wrong-review-group-title {
  font-family: 'Outfit', sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
  flex: 1;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.wrong-review-group-count {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--text-muted);
}

.wrong-review-group-list {
  display: none;
  flex-direction: column;
  gap: var(--space-lg);
  padding: var(--space-md) var(--space-lg) var(--space-lg);
  border-top: 1px solid var(--border-color);
  background: var(--bg-primary);
}

.wrong-review-group--expanded .wrong-review-group-list {
  display: flex;
}

.wrong-review-group-list .review-item {
  margin-bottom: 0;
}

.review-topic-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-cyan);
  background: rgba(6, 182, 212, 0.15);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  margin-right: var(--space-sm);
}

/* Wrong Review pagination */
.wrong-review-pagination {
  margin-bottom: var(--space-lg);
}

.wrong-review-pagination:last-of-type {
  margin-bottom: 0;
  margin-top: var(--space-xl);
}

.pagination-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--border-color);
}

.pagination-bar:last-of-type {
  border-bottom: none;
  border-top: 1px solid var(--border-color);
}

.pagination-info {
  font-size: 0.9rem;
  color: var(--text-muted);
}

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

.pagination-btn {
  padding: var(--space-sm) var(--space-lg);
  font-size: 0.9rem;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  cursor: pointer;
  transition: background var(--transition-fast), border-color var(--transition-fast);
}

.pagination-btn:hover:not(:disabled) {
  background: rgba(59, 130, 246, 0.1);
  border-color: var(--accent-blue);
}

.pagination-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

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

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

/* Visible utility */
.visible {
  display: block !important;
}