/* ==========================================================
   Aviation TCP Study - Modern Cockpit UI System
   ========================================================== */

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

:root {
  /* Dark Theme (Default Avionics Dark) */
  --bg-primary: #070d18;
  --bg-secondary: #0e1726;
  --bg-card: #131f37;
  --bg-card-hover: #182846;
  --bg-input: #1b2a47;
  --border-color: #223558;
  --border-focus: #00b4d8;
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --color-primary: #00b4d8;
  --color-primary-glow: rgba(0, 180, 216, 0.25);
  --color-accent: #38bdf8;
  --color-gold: #fbbf24;
  --color-gold-glow: rgba(251, 191, 36, 0.2);
  
  --color-success: #10b981;
  --color-success-bg: rgba(16, 185, 129, 0.15);
  --color-success-border: #059669;
  
  --color-danger: #ef4444;
  --color-danger-bg: rgba(239, 68, 68, 0.15);
  --color-danger-border: #dc2626;

  --color-warning: #f59e0b;
  --color-warning-bg: rgba(245, 158, 11, 0.15);

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 36px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 20px rgba(0, 180, 216, 0.2);

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-primary: #f1f5f9;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f8fafc;
  --bg-input: #f1f5f9;
  --border-color: #cbd5e1;
  --border-focus: #0284c7;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --color-primary: #0284c7;
  --color-primary-glow: rgba(2, 132, 199, 0.15);
  --color-accent: #0369a1;
  --color-gold: #d97706;
  --color-gold-glow: rgba(217, 119, 6, 0.15);
  
  --color-success: #059669;
  --color-success-bg: #ecfdf5;
  --color-success-border: #10b981;
  
  --color-danger: #dc2626;
  --color-danger-bg: #fef2f2;
  --color-danger-border: #ef4444;

  --color-warning: #d97706;
  --color-warning-bg: #fffbeb;

  --shadow-sm: 0 2px 6px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 6px 18px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 30px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 15px rgba(2, 132, 199, 0.12);
}

/* ==========================================================
   Base & Reset
   ========================================================== */

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  outline: none;
  background: none;
  transition: all var(--transition-fast);
}

/* ==========================================================
   Layout Containers
   ========================================================== */

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ==========================================================
   Header & Navbar
   ========================================================== */

.app-header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  padding: 0.85rem 0;
  box-shadow: var(--shadow-sm);
}

.nav-wrapper {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: 'Outfit', sans-serif;
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  cursor: pointer;
}

.brand-icon-wrapper {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-primary), #0284c7);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.1rem;
  box-shadow: var(--shadow-glow);
}

.brand-badge {
  font-size: 0.65rem;
  font-weight: 700;
  background-color: var(--color-primary-glow);
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-full);
  margin-left: 0.4rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.btn-icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 1rem;
}

.btn-icon:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  transform: translateY(-1px);
}

/* ==========================================================
   Hero & Featured Quick Start Banner
   ========================================================== */

.hero-banner {
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  padding: 2rem 0 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.hero-cta-card {
  background: linear-gradient(135deg, rgba(0, 180, 216, 0.12), rgba(14, 23, 38, 0.95)), var(--bg-card);
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 1.75rem;
  display: grid;
  grid-template-columns: 1.3fr 0.9fr;
  gap: 2rem;
  align-items: center;
  box-shadow: 0 12px 32px rgba(0, 180, 216, 0.15);
  position: relative;
  overflow: hidden;
}

.hero-cta-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  background-color: var(--color-gold-glow);
  border: 1px solid var(--color-gold);
  color: var(--color-gold);
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 0.82rem;
  padding: 0.35rem 0.85rem;
  border-radius: var(--radius-full);
  margin-bottom: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero-cta-title {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.hero-cta-title span {
  background: linear-gradient(135deg, var(--color-primary), #38bdf8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-cta-desc {
  font-size: 1.02rem;
  color: var(--text-secondary);
  line-height: 1.55;
  margin-bottom: 1.5rem;
}

.hero-cta-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

/* Pulsing Primary Button */
.btn-pulse {
  background: linear-gradient(135deg, #00b4d8, #0284c7);
  color: #ffffff !important;
  font-family: 'Outfit', sans-serif;
  font-size: 1.12rem;
  font-weight: 700;
  padding: 0.9rem 1.85rem;
  border-radius: var(--radius-md);
  box-shadow: 0 0 0 0 rgba(0, 180, 216, 0.7);
  animation: pulseGlow 2s infinite;
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-pulse:hover {
  transform: translateY(-2px) scale(1.02);
  background: linear-gradient(135deg, #38bdf8, #0369a1);
  box-shadow: 0 8px 24px rgba(0, 180, 216, 0.45);
}

@keyframes pulseGlow {
  0% {
    box-shadow: 0 0 0 0 rgba(0, 180, 216, 0.6);
  }
  70% {
    box-shadow: 0 0 0 14px rgba(0, 180, 216, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(0, 180, 216, 0);
  }
}

.hero-img-box {
  width: 100%;
  height: 230px;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-md);
  position: relative;
}

.hero-img-box img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-normal);
}

.hero-img-box:hover img {
  transform: scale(1.03);
}

.hero-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.hero-title-area h1 {
  font-size: 2rem;
  margin-bottom: 0.35rem;
}

.hero-title-area p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  max-width: 600px;
}

.stats-grid-mini {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.stat-chip {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.65rem 1.1rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  box-shadow: var(--shadow-sm);
}

.stat-chip-icon {
  font-size: 1.25rem;
  color: var(--color-primary);
}

.stat-chip.missed .stat-chip-icon {
  color: var(--color-danger);
}

.stat-chip-info {
  display: flex;
  flex-direction: column;
}

.stat-chip-num {
  font-family: 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.1;
}

.stat-chip-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 600;
}

/* ==========================================================
   Navigation Tabs
   ========================================================== */

.tabs-nav {
  display: flex;
  gap: 0.5rem;
  margin: 1.75rem 0 1.25rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.5rem;
  overflow-x: auto;
}

.tab-btn {
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
}

.tab-btn i {
  font-size: 1rem;
}

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

.tab-btn.active {
  color: var(--color-primary);
  background-color: var(--color-primary-glow);
  border: 1px solid var(--color-primary);
}

.tab-btn .badge-counter {
  background-color: var(--color-danger);
  color: #fff;
  font-size: 0.7rem;
  padding: 0.1rem 0.45rem;
  border-radius: var(--radius-full);
  font-weight: 700;
}

/* ==========================================================
   Section Views
   ========================================================== */

.view-section {
  display: none;
  animation: fadeIn 0.3s ease-in-out;
  padding-bottom: 4rem;
}

.view-section.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==========================================================
   Modules Grid
   ========================================================== */

.section-header {
  margin-bottom: 1.5rem;
}

.section-header h2 {
  font-size: 1.45rem;
  margin-bottom: 0.25rem;
}

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

.modules-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.25rem;
}

.module-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.4rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.module-card:hover {
  transform: translateY(-3px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.module-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.module-icon-badge {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(0, 180, 216, 0.15), rgba(2, 132, 199, 0.25));
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-size: 1.25rem;
}

.module-tag {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-full);
  background-color: var(--bg-input);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.module-title {
  font-size: 1.15rem;
  margin-bottom: 0.5rem;
  line-height: 1.3;
}

.module-desc {
  font-size: 0.86rem;
  color: var(--text-secondary);
  margin-bottom: 1.25rem;
  flex-grow: 1;
}

.module-stats-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background-color: var(--bg-secondary);
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  margin-bottom: 1rem;
  font-size: 0.82rem;
}

.module-best-score {
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.module-best-score.passed {
  color: var(--color-success);
}

.module-best-score.failed {
  color: var(--color-danger);
}

.module-best-score.none {
  color: var(--text-muted);
}

/* Module Video Thumbnail Card */
.module-video-thumb-card {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-bottom: 0.85rem;
  cursor: pointer;
  border: 1px solid var(--border-color);
  background-color: #000;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.module-video-thumb-card:hover {
  border-color: #ef4444;
  transform: translateY(-2px);
  box-shadow: 0 8px 22px rgba(239, 68, 68, 0.3);
}

.module-video-thumb-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.4s ease-out;
}

.module-video-thumb-card:hover .module-video-thumb-img {
  transform: scale(1.06);
}

.module-video-thumb-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(180deg, rgba(0, 0, 0, 0.2) 0%, rgba(0, 0, 0, 0.65) 100%);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 0.65rem 0.85rem;
  transition: background var(--transition-fast);
}

.module-video-thumb-card:hover .module-video-thumb-overlay {
  background: linear-gradient(180deg, rgba(0, 0, 0, 0.1) 0%, rgba(0, 0, 0, 0.8) 100%);
}

.module-video-badge-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.module-video-tag {
  background: rgba(0, 0, 0, 0.75);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.2rem 0.55rem;
  border-radius: var(--radius-sm);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  gap: 0.35rem;
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.module-video-play-btn {
  width: 46px;
  height: 46px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, #ef4444, #e11d48);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  box-shadow: 0 4px 16px rgba(239, 68, 68, 0.6);
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.module-video-thumb-card:hover .module-video-play-btn {
  transform: translate(-50%, -50%) scale(1.15);
  box-shadow: 0 6px 24px rgba(239, 68, 68, 0.85);
}

.module-video-bottom-title {
  color: #fff;
  font-size: 0.78rem;
  font-weight: 600;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.9);
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.module-actions {
  display: flex;
  gap: 0.65rem;
}

.btn {
  padding: 0.65rem 1.1rem;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.88rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  text-align: center;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), #0284c7);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(0, 180, 216, 0.3);
  flex: 1;
}

.btn-primary:hover {
  background: linear-gradient(135deg, #38bdf8, #0369a1);
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(0, 180, 216, 0.4);
}

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

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

/* ==========================================================
   Special Modes Cards
   ========================================================== */

.special-modes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.25rem;
  margin-top: 1rem;
}

.special-card {
  background: linear-gradient(135deg, var(--bg-card), var(--bg-secondary));
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
  position: relative;
  overflow: hidden;
}

.special-card.mock {
  border-left: 4px solid var(--color-gold);
}

.special-card.missed-mode {
  border-left: 4px solid var(--color-danger);
}

.special-card.bookmark-mode {
  border-left: 4px solid var(--color-primary);
}

.special-card h3 {
  font-size: 1.25rem;
  margin: 0.5rem 0;
}

.special-card p {
  color: var(--text-secondary);
  font-size: 0.88rem;
  margin-bottom: 1.25rem;
}

/* ==========================================================
   Quiz Interface (Active Test View)
   ========================================================== */

.quiz-container {
  max-width: 800px;
  margin: 1.5rem auto 3rem;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-md);
}

.quiz-header-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.quiz-meta-info h2 {
  font-size: 1.25rem;
  line-height: 1.2;
}

.quiz-meta-info span {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.quiz-top-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.timer-badge {
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--color-primary);
}

.progress-track {
  width: 100%;
  height: 8px;
  background-color: var(--bg-input);
  border-radius: var(--radius-full);
  overflow: hidden;
  margin-bottom: 1.5rem;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  width: 0%;
  transition: width 0.3s ease;
  border-radius: var(--radius-full);
}

.question-card {
  margin-bottom: 1.5rem;
}

.question-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.question-num-tag {
  font-family: 'Outfit', sans-serif;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.question-topic-tag {
  font-size: 0.75rem;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full);
  border: 1px solid var(--border-color);
}

.question-text {
  font-size: 1.18rem;
  font-weight: 600;
  line-height: 1.45;
  color: var(--text-primary);
  margin-bottom: 1.5rem;
}

/* Options Grid */

.options-list {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin-bottom: 1.5rem;
}

.option-item {
  background-color: var(--bg-secondary);
  border: 1.5px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.15rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  text-align: left;
  font-size: 0.95rem;
  color: var(--text-primary);
  transition: all var(--transition-fast);
  cursor: pointer;
  position: relative;
}

.option-item:hover:not(.disabled) {
  border-color: var(--color-primary);
  background-color: var(--bg-card-hover);
  transform: translateX(4px);
}

.option-letter {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--text-secondary);
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.option-text {
  flex-grow: 1;
}

/* Option States */
.option-item.selected {
  border-color: var(--color-primary);
  background-color: var(--color-primary-glow);
}
.option-item.selected .option-letter {
  background-color: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.option-item.correct {
  border-color: var(--color-success);
  background-color: var(--color-success-bg);
}
.option-item.correct .option-letter {
  background-color: var(--color-success);
  color: #fff;
  border-color: var(--color-success);
}

.option-item.incorrect {
  border-color: var(--color-danger);
  background-color: var(--color-danger-bg);
}
.option-item.incorrect .option-letter {
  background-color: var(--color-danger);
  color: #fff;
  border-color: var(--color-danger);
}

.option-item.disabled {
  cursor: default;
}

/* Explanation Card */
.explanation-card {
  background-color: var(--bg-secondary);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius-md);
  padding: 1.15rem;
  margin-bottom: 1.5rem;
  animation: fadeIn 0.25s ease;
  border-top: 1px solid var(--border-color);
  border-right: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.explanation-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 0.4rem;
  color: var(--color-primary);
}

.explanation-card.correct-exp {
  border-left-color: var(--color-success);
}
.explanation-card.correct-exp .explanation-header {
  color: var(--color-success);
}

.explanation-card.incorrect-exp {
  border-left-color: var(--color-danger);
}
.explanation-card.incorrect-exp .explanation-header {
  color: var(--color-danger);
}

.explanation-body {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* Quiz Bottom Controls */
.quiz-bottom-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.25rem;
}

/* ==========================================================
   Results Screen View
   ========================================================== */

.results-wrapper {
  max-width: 850px;
  margin: 1.5rem auto 3rem;
}

.result-hero-card {
  background: linear-gradient(180deg, var(--bg-card) 0%, var(--bg-secondary) 100%);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2.2rem;
  text-align: center;
  box-shadow: var(--shadow-lg);
  margin-bottom: 1.75rem;
  position: relative;
}

.result-badge-status {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1.25rem;
  border-radius: var(--radius-full);
  font-family: 'Outfit', sans-serif;
  font-weight: 800;
  font-size: 1.1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 1rem;
}

.result-badge-status.passed {
  background-color: var(--color-success-bg);
  color: var(--color-success);
  border: 1px solid var(--color-success);
}

.result-badge-status.failed {
  background-color: var(--color-danger-bg);
  color: var(--color-danger);
  border: 1px solid var(--color-danger);
}

.score-big-display {
  font-family: 'Outfit', sans-serif;
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1;
  margin-bottom: 0.5rem;
}

.score-big-display span {
  font-size: 1.5rem;
  color: var(--text-muted);
}

.result-meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  margin: 1.75rem 0 1.5rem;
}

.result-stat-box {
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.85rem;
}

.result-stat-val {
  font-family: 'Outfit', sans-serif;
  font-size: 1.4rem;
  font-weight: 700;
}

.result-stat-lbl {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

.results-action-buttons {
  display: flex;
  gap: 0.85rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Detailed Review Accordion / Cards */
.review-section-container {
  margin-top: 2rem;
}

.review-filter-bar {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.filter-chip {
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-full);
  font-size: 0.82rem;
  font-weight: 600;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
}

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

.review-item-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 1rem;
}

.review-item-card.correct-item {
  border-left: 4px solid var(--color-success);
}

.review-item-card.incorrect-item {
  border-left: 4px solid var(--color-danger);
}

/* ==========================================================
   Topic Review & Cheat Sheet View
   ========================================================== */

.topics-accordion {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.topic-accordion-item {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.topic-accordion-header {
  padding: 1.2rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  background-color: var(--bg-card);
  transition: background-color var(--transition-fast);
}

.topic-accordion-header:hover {
  background-color: var(--bg-card-hover);
}

.topic-header-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.topic-header-title h3 {
  font-size: 1.1rem;
}

.topic-accordion-body {
  display: none;
  padding: 1.5rem;
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
}

.topic-accordion-body.open {
  display: block;
  animation: fadeIn 0.2s ease;
}

.key-concepts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.concept-box {
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem;
}

.concept-box h4 {
  font-size: 0.95rem;
  color: var(--color-primary);
  margin-bottom: 0.35rem;
}

.concept-box p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.acronyms-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 0.75rem;
  font-size: 0.85rem;
}

.acronyms-table th, .acronyms-table td {
  padding: 0.6rem 0.85rem;
  border: 1px solid var(--border-color);
  text-align: left;
}

.acronyms-table th {
  background-color: var(--bg-input);
  color: var(--text-primary);
  font-family: 'Outfit', sans-serif;
}

/* ==========================================================
   History & Stats View
   ========================================================== */

.history-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.history-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.history-score-badge {
  font-family: 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-md);
}

.history-score-badge.passed {
  background-color: var(--color-success-bg);
  color: var(--color-success);
}

.history-score-badge.failed {
  background-color: var(--color-danger-bg);
  color: var(--color-danger);
}

/* ==========================================================
   Footer
   ========================================================== */

.app-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  padding: 1.5rem 0;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
}

/* ==========================================================
   Multimedia Player & Video Modal Controls
   ========================================================== */

.media-buttons-row {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  margin-top: 0.65rem;
  margin-bottom: 0.85rem;
}

.btn-video-pill {
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.12), rgba(244, 63, 94, 0.18));
  border: 1px solid rgba(239, 68, 68, 0.4);
  color: #f43f5e;
  font-size: 0.82rem;
  font-weight: 700;
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  transition: all var(--transition-fast);
  cursor: pointer;
  width: 100%;
  justify-content: center;
  box-shadow: 0 2px 8px rgba(244, 63, 94, 0.15);
}

.btn-video-pill:hover {
  background: linear-gradient(135deg, #ef4444, #e11d48);
  color: #fff;
  border-color: #ef4444;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(244, 63, 94, 0.35);
}

.btn-audio-pill {
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--color-primary);
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius-full);
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  transition: all var(--transition-fast);
  cursor: pointer;
  width: 100%;
  justify-content: center;
}

.btn-audio-pill:hover {
  background-color: var(--color-primary-glow);
  border-color: var(--color-primary);
  transform: translateY(-1px);
}

.btn-audio-pill.playing {
  background: linear-gradient(135deg, var(--color-primary), #0284c7);
  color: #fff;
  border-color: var(--color-primary);
}

.topic-multimedia-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

@media (max-width: 768px) {
  .topic-multimedia-grid {
    grid-template-columns: 1fr;
  }
}

.multimedia-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.85rem;
  transition: all var(--transition-fast);
}

.multimedia-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
}

.multimedia-card.video-card {
  border-color: rgba(239, 68, 68, 0.3);
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.06), var(--bg-card));
}

.multimedia-card.video-card:hover {
  border-color: #ef4444;
}

.multimedia-icon {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  color: #fff;
  flex-shrink: 0;
}

.multimedia-icon.video-icon {
  background: linear-gradient(135deg, #ef4444, #e11d48);
  box-shadow: 0 4px 12px rgba(239, 68, 68, 0.35);
}

.multimedia-icon.audio-icon {
  background: linear-gradient(135deg, var(--color-primary), #0284c7);
  box-shadow: 0 4px 12px rgba(0, 180, 216, 0.3);
}

.multimedia-info h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.15rem;
}

.multimedia-info p {
  font-size: 0.78rem;
  color: var(--text-secondary);
}

/* Video Modal */
.video-modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(10px);
  z-index: 2000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  animation: fadeIn 0.25s ease-out;
}

.video-modal-backdrop.active {
  display: flex;
}

.video-modal-dialog {
  background-color: var(--bg-card);
  border: 2px solid var(--color-primary);
  border-radius: var(--radius-lg);
  max-width: 800px;
  width: 100%;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.7), var(--shadow-glow);
  overflow: hidden;
  animation: zoomIn 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes zoomIn {
  from { transform: scale(0.92); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

.video-modal-header {
  padding: 1rem 1.5rem;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.video-modal-title {
  font-size: 1.1rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.video-modal-body {
  padding: 0;
  background-color: #000;
  position: relative;
}

.video-modal-element {
  width: 100%;
  max-height: 480px;
  aspect-ratio: 16/9;
  display: block;
  background-color: #000;
}

.video-modal-footer {
  padding: 1rem 1.5rem;
  background: var(--bg-card);
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* Global Sticky Audio Player Bar */
.global-audio-player {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: rgba(14, 23, 38, 0.95);
  backdrop-filter: blur(16px);
  border-top: 2px solid var(--color-primary);
  padding: 0.75rem 1.5rem;
  z-index: 1000;
  box-shadow: 0 -8px 24px rgba(0, 0, 0, 0.5);
  display: none;
  animation: slideUp 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.global-audio-player.active {
  display: block;
}

@keyframes slideUp {
  from { transform: translateY(100%); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.audio-player-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.audio-track-details {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  min-width: 240px;
}

.audio-track-details h4 {
  font-size: 0.92rem;
  line-height: 1.2;
  margin-bottom: 0.15rem;
}

.audio-track-details span {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.audio-center-controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-grow: 1;
  max-width: 550px;
  gap: 0.35rem;
}

.audio-btn-row {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.btn-audio-circle {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-audio-circle:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-audio-circle.play-btn-main {
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--color-primary), #0284c7);
  color: #fff;
  border-color: var(--color-primary);
  font-size: 1.15rem;
  box-shadow: 0 4px 12px rgba(0, 180, 216, 0.4);
}

.btn-audio-circle.play-btn-main:hover {
  transform: scale(1.06);
}

.audio-timeline-box {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.audio-time-label {
  font-size: 0.72rem;
  font-family: 'Outfit', sans-serif;
  color: var(--text-muted);
  width: 38px;
  text-align: center;
}

.audio-scrubber {
  flex-grow: 1;
  height: 6px;
  -webkit-appearance: none;
  background: var(--bg-input);
  border-radius: var(--radius-full);
  outline: none;
  cursor: pointer;
}

.audio-scrubber::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  box-shadow: 0 0 6px rgba(0, 180, 216, 0.8);
}

.audio-right-controls {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.speed-select-btn {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-family: 'Outfit', sans-serif;
  font-weight: 700;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
}

.speed-select-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ==========================================================
   Responsive Adaptations
   ========================================================== */

@media (max-width: 768px) {
  .hero-cta-card {
    grid-template-columns: 1fr;
    padding: 1.5rem;
  }
  .hero-img-box {
    height: 180px;
  }
  .hero-cta-title {
    font-size: 1.75rem;
  }
  .hero-content {
    flex-direction: column;
    align-items: flex-start;
  }
  .stats-grid-mini {
    width: 100%;
  }
  .stat-chip {
    flex: 1;
  }
  .modules-grid {
    grid-template-columns: 1fr;
  }
  .quiz-container {
    padding: 1.2rem;
  }
  .option-item {
    padding: 0.85rem 1rem;
    font-size: 0.9rem;
  }
  .score-big-display {
    font-size: 2.75rem;
  }
  .audio-player-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 0.75rem;
  }
  .audio-track-details {
    justify-content: space-between;
  }
}