:root {
  --bg-primary: #0a0d18;
  --bg-secondary: #121729;
  --bg-card: rgba(18, 24, 44, 0.78);
  --bg-card-hover: rgba(28, 38, 68, 0.88);
  --border-color: rgba(99, 102, 241, 0.2);
  --border-glow: rgba(99, 102, 241, 0.4);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-primary: #6366f1;
  --accent-hover: #4f46e5;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 50%, #ec4899 100%);
  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.15);
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.15);
  --warning: #f59e0b;
  --warning-bg: rgba(245, 158, 11, 0.15);
  --info: #06b6d4;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 25px rgba(99, 102, 241, 0.25);
  --font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
  --bg-primary: #f6f2e8;
  --bg-secondary: #fdfaf3;
  --bg-card: rgba(255, 253, 248, 0.88);
  --bg-card-hover: #ffffff;
  --border-color: rgba(160, 120, 80, 0.2);
  --border-glow: rgba(190, 135, 75, 0.35);
  --text-primary: #1e2432;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --shadow-sm: 0 2px 8px rgba(60, 45, 30, 0.06);
  --shadow-md: 0 8px 20px rgba(60, 45, 30, 0.08);
  --shadow-lg: 0 16px 36px rgba(60, 45, 30, 0.12);
}

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

html {
  background-color: var(--bg-primary);
  min-height: 100%;
}

body {
  font-family: var(--font-family);
  background-color: transparent;
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
}

/* Authentic Dong Ho Folk Painting Watermarked / In Chìm Background */
body::before {
  content: "";
  position: fixed;
  top: -15px;
  left: -15px;
  right: -15px;
  bottom: -15px;
  z-index: -1;
  background-image: url('../assets/dongho_bg.jpg');
  background-position: center center;
  background-repeat: no-repeat;
  background-size: cover;
  pointer-events: none;
  /* Dark mode: subtly illuminated lacquer woodblock watermark */
  opacity: 0.22;
  filter: blur(2px) brightness(0.8) contrast(1.15) saturate(1.1);
  transform: translateZ(0);
  transition: opacity 0.3s ease, filter 0.3s ease;
}

/* Soft Vignette Overlay for Crisp Reading Comfort */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background: radial-gradient(circle at 50% 35%, rgba(10, 13, 24, 0.1) 0%, rgba(10, 13, 24, 0.55) 100%);
  transition: background 0.3s ease;
}

[data-theme="light"] body::before {
  /* Light mode: authentic Giấy Dó / Giấy Điệp watermark, softly pressed into the paper */
  opacity: 0.26;
  filter: blur(1.5px) saturate(0.95) contrast(1.05);
  mix-blend-mode: multiply;
}

[data-theme="light"] body::after {
  background: radial-gradient(circle at 50% 35%, rgba(246, 242, 232, 0.1) 0%, rgba(240, 234, 222, 0.35) 100%);
}

/* Nav Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 13, 24, 0.85);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-color);
  padding: 0.75rem 1.5rem;
}

[data-theme="light"] .site-header {
  background: rgba(246, 242, 232, 0.88);
}

.header-container {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-area {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  text-decoration: none;
  color: inherit;
}

.brand-logo-badge {
  background: var(--accent-gradient);
  color: white;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.15rem;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.35);
}

.brand-text h1 {
  font-size: 1.15rem;
  font-weight: 700;
  line-height: 1.2;
  background: linear-gradient(135deg, #ffffff 0%, #cbd5e1 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="light"] .brand-text h1 {
  background: linear-gradient(135deg, #0f172a 0%, #334155 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-text p {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

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

.btn-icon {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition);
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6rem 1.25rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
}

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

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
  transform: translateY(-1px);
}

.btn-danger {
  background: var(--error);
  color: white;
}

.btn-success {
  background: var(--success);
  color: white;
}

/* Home Portal Styles */
.portal-hero {
  max-width: 1200px;
  margin: 2.5rem auto 1.5rem;
  padding: 0 1.5rem;
  text-align: center;
}

.portal-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 1rem;
  border-radius: 9999px;
  background: rgba(99, 102, 241, 0.15);
  border: 1px solid rgba(99, 102, 241, 0.35);
  color: #a5b4fc;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.portal-hero h1 {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #ffffff 0%, #cbd5e1 50%, #94a3b8 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

[data-theme="light"] .portal-hero h1 {
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.portal-hero p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 750px;
  margin: 0 auto 1.75rem;
}

.features-banner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  max-width: 1200px;
  margin: 0 auto 2.5rem;
  padding: 0 1.5rem;
}

.feature-pill {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  gap: 0.85rem;
  backdrop-filter: blur(10px);
}

.feature-pill-icon {
  font-size: 1.6rem;
}

.feature-pill-text h4 {
  font-size: 0.95rem;
  font-weight: 700;
}

.feature-pill-text p {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* Test Cards Grid */
.tests-grid-section {
  max-width: 1200px;
  margin: 2rem auto 3rem;
  padding: 0 1.5rem;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
}

.section-header h2 {
  font-size: 1.5rem;
  font-weight: 700;
}

.test-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.5rem;
}

.test-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(10px);
}

.test-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--accent-gradient);
  opacity: 0.8;
}

.test-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-primary);
  box-shadow: var(--shadow-glow);
}

.test-card-top {
  margin-bottom: 1.25rem;
}

.test-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 0.75rem;
}

.tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: 9999px;
  background: rgba(99, 102, 241, 0.15);
  color: #a5b4fc;
}

.tag-warning {
  background: var(--warning-bg);
  color: var(--warning);
}

.tag-success {
  background: var(--success-bg);
  color: var(--success);
}

.test-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.test-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 1rem;
}

.test-meta-stats {
  display: flex;
  align-items: center;
  gap: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  padding-top: 0.75rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  margin-bottom: 1.25rem;
}

.test-meta-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.test-card-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

/* Quiz Interface Layout
   Desktop: full-viewport exam room, each column scrolls on its own.
   Below 1024px: falls back to normal page scrolling. */
.quiz-page {
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

.quiz-page .site-header {
  position: relative;
  padding: 0.55rem 1.25rem;
}

.quiz-page .header-container {
  max-width: none;
}

.quiz-wrapper {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.quiz-topbar {
  background: rgba(18, 23, 41, 0.78);
  border-bottom: 1px solid var(--border-color);
  padding: 0.6rem 1.25rem;
  position: relative;
  z-index: 90;
  backdrop-filter: blur(14px);
}

[data-theme="light"] .quiz-topbar {
  background: rgba(253, 250, 243, 0.82);
}

.quiz-topbar-content {
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.quiz-info-group {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.timer-box {
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid rgba(245, 158, 11, 0.35);
  color: var(--warning);
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-family: monospace;
  font-size: 1.15rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.timer-box.urgent {
  background: var(--error-bg);
  border-color: var(--error);
  color: var(--error);
  animation: pulse-urgent 1s infinite;
}

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

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

/* Section Navigation Tabs (Tách riêng Listening và Reading) */
.quiz-section-nav {
  margin-top: 0.65rem;
  padding-top: 0.65rem;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

[data-theme="light"] .quiz-section-nav {
  border-top-color: rgba(0, 0, 0, 0.06);
}

.section-tabs-wrapper {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.section-tab-btn {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.55rem 1rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  cursor: pointer;
  transition: var(--transition);
  text-align: left;
  position: relative;
  overflow: hidden;
}

[data-theme="light"] .section-tab-btn {
  background: rgba(0, 0, 0, 0.03);
}

.section-tab-btn:hover {
  background: rgba(99, 102, 241, 0.1);
  border-color: rgba(99, 102, 241, 0.4);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.section-tab-btn.active {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.22) 0%, rgba(168, 85, 247, 0.15) 100%);
  border-color: var(--accent-primary);
  color: #ffffff;
  box-shadow: 0 4px 16px rgba(99, 102, 241, 0.2);
}

[data-theme="light"] .section-tab-btn.active {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(168, 85, 247, 0.1) 100%);
  color: var(--accent-primary);
}

.section-tab-icon {
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.06);
  flex-shrink: 0;
}

.section-tab-btn.active .section-tab-icon {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 0 12px rgba(99, 102, 241, 0.4);
}

.section-tab-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.section-tab-title {
  font-weight: 700;
  font-size: 0.92rem;
  letter-spacing: 0.01em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.section-tab-desc {
  font-size: 0.76rem;
  opacity: 0.8;
  margin-top: 1px;
}

/* Split Screen Layout for Reading & Questions
   Passage (wide) | Questions (narrower) | Palette (fixed) */
.quiz-main-container {
  width: 100%;
  padding: 1rem 1.25rem;
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(380px, 5fr) 236px;
  grid-template-rows: minmax(0, 1fr);
  gap: 1.25rem;
  flex: 1;
  min-height: 0;
  align-items: stretch;
}

/* Layout in Listening Mode: Clean, focused, no passage pane distraction */
.quiz-main-container.section-mode-listening {
  grid-template-columns: minmax(0, 1fr) 246px;
  max-width: 1350px;
  margin: 0 auto;
}

.quiz-main-container.section-mode-listening #passagePane {
  display: none !important;
}

.quiz-main-container.section-mode-listening .questions-pane {
  max-width: 960px;
  margin: 0 auto;
  width: 100%;
}

/* Layout in Reading Mode: Split-Screen view with synced passage */
.quiz-main-container.section-mode-reading {
  grid-template-columns: minmax(0, 7fr) minmax(380px, 5fr) 236px;
}

.quiz-main-container.section-mode-reading #passagePane {
  display: flex;
}

.passage-pane,
.questions-pane,
.palette-pane {
  min-height: 0;
  scrollbar-width: thin;
  scrollbar-color: rgba(99, 102, 241, 0.35) transparent;
}

/* Passage Sidebar Pane */
.passage-pane {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.1rem 1.25rem 0 1.5rem;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  backdrop-filter: blur(10px);
}

.passage-pane-header {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.65rem;
  border-bottom: 1px solid var(--border-color);
}

.passage-pane-header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.passage-live-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: rgba(99, 102, 241, 0.2);
  color: #a5b4fc;
  border: 1px solid rgba(99, 102, 241, 0.4);
  padding: 0.22rem 0.65rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
}

.live-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-primary);
  box-shadow: 0 0 8px var(--accent-primary);
  animation: pulseDot 1.5s infinite;
}

.btn-sync-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  cursor: pointer;
  transition: var(--transition);
}

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

.btn-sync-toggle.active {
  background: rgba(16, 185, 129, 0.15);
  border-color: var(--success);
  color: var(--success);
}

.passage-title-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.passage-title-row h3 {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--text-primary);
}

.passage-range-tag {
  font-size: 0.78rem;
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.05);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
}

.passage-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border-color);
}

.passage-tab {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  border-radius: 9999px;
  padding: 0.32rem 0.8rem;
  font-family: inherit;
  font-size: 0.78rem;
  font-weight: 600;
  white-space: nowrap;
  cursor: pointer;
  transition: var(--transition);
}

[data-theme="light"] .passage-tab {
  background: rgba(0, 0, 0, 0.03);
}

.passage-tab:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

.passage-tab.active {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: #fff;
}

.passage-tab-range {
  font-weight: 500;
  opacity: 0.75;
  margin-left: 0.3rem;
}

.passage-content {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  position: relative;
  padding: 1rem 0.75rem 1.5rem 0;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--text-primary);
  scrollbar-width: thin;
  scrollbar-color: rgba(99, 102, 241, 0.35) transparent;
}

.passage-content p {
  margin-bottom: 0.9rem;
}

.passage-content .passage-instruction {
  font-size: 0.9rem;
  font-style: italic;
  color: var(--text-secondary);
}

.passage-content .passage-title {
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-align: center;
  margin: 0.25rem 0 1rem;
}

.passage-content .passage-item {
  padding-left: 1.6rem;
  text-indent: -1.6rem;
  margin-bottom: 0.45rem;
}

.passage-gap {
  display: inline-block;
  padding: 0 0.4rem;
  border-radius: 6px;
  border: 1px solid rgba(99, 102, 241, 0.45);
  background: rgba(99, 102, 241, 0.16);
  font-weight: 700;
  font-size: 0.88em;
  line-height: 1.5;
  text-indent: 0;
  cursor: pointer;
  transition: var(--transition);
}

.passage-gap:hover {
  border-color: var(--accent-primary);
}

.passage-gap.active {
  background: var(--accent-gradient);
  border-color: transparent;
  color: #fff;
  box-shadow: 0 0 12px rgba(99, 102, 241, 0.45);
}

.passage-gap.active-focus {
  background: var(--accent-gradient) !important;
  color: #ffffff !important;
  box-shadow: 0 0 18px rgba(99, 102, 241, 0.7), 0 0 0 2px rgba(255, 255, 255, 0.6) !important;
  transform: scale(1.15);
  animation: pulseActiveGap 2s infinite ease-in-out;
}

@keyframes pulseActiveGap {
  0%, 100% { box-shadow: 0 0 16px rgba(99, 102, 241, 0.6), 0 0 0 2px rgba(255, 255, 255, 0.5); }
  50% { box-shadow: 0 0 24px rgba(236, 72, 153, 0.8), 0 0 0 3px rgba(255, 255, 255, 0.8); }
}

/* Paragraph numbering in Reading Comprehension */
.passage-content .passage-para {
  position: relative;
  padding-left: 2.2rem;
  margin-bottom: 1.1rem;
  transition: background 0.25s ease, border-color 0.25s ease;
}

.passage-content .passage-para[data-para]::before {
  content: attr(data-para);
  position: absolute;
  left: 0;
  top: 0.15rem;
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.05);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  user-select: none;
}

[data-theme="light"] .passage-content .passage-para[data-para]::before {
  background: rgba(0, 0, 0, 0.04);
  border-color: rgba(0, 0, 0, 0.08);
}

.passage-content .passage-para.highlight-focus {
  background: rgba(99, 102, 241, 0.08);
  border-left: 3px solid var(--accent-primary);
  padding-left: calc(2.2rem + 6px);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* Text that reading questions point to: underlined sentences, bold words, [I]–[IV] slots */
.passage-content u {
  text-decoration-color: var(--accent-primary);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.passage-content strong {
  font-weight: 800;
}

.passage-marker {
  font-weight: 700;
  font-size: 0.88em;
  color: var(--accent-primary);
  white-space: nowrap;
}

/* Empty State Card when question has no passage */
.passage-empty-card {
  padding: 2.5rem 1.5rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  color: var(--text-secondary);
  animation: fadeIn 0.3s ease;
}

.passage-empty-card .empty-icon {
  font-size: 2.8rem;
  margin-bottom: 0.75rem;
  opacity: 0.9;
}

.passage-empty-card h4 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
}

.passage-empty-card .empty-badge {
  display: inline-block;
  background: rgba(99, 102, 241, 0.15);
  color: #a5b4fc;
  border: 1px solid rgba(99, 102, 241, 0.3);
  padding: 0.2rem 0.65rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.passage-empty-card p {
  font-size: 0.9rem;
  max-width: 320px;
  line-height: 1.6;
  margin-bottom: 1rem;
}

.passage-empty-card .empty-tip {
  font-size: 0.8rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px dashed var(--border-color);
  padding: 0.6rem 0.85rem;
  border-radius: var(--radius-sm);
  max-width: 340px;
  color: var(--text-muted);
}

/* Section Switch and Intro Cards */
.section-switch-card {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(168, 85, 247, 0.12) 100%);
  border: 1px solid rgba(99, 102, 241, 0.4);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.25rem;
  flex-wrap: wrap;
  margin-top: 1rem;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.switch-card-icon {
  font-size: 2rem;
  background: rgba(99, 102, 241, 0.2);
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.switch-card-body {
  flex: 1;
  min-width: 240px;
}

.switch-card-body h4 {
  font-size: 1.05rem;
  font-weight: 700;
  color: #c7d2fe;
  margin-bottom: 0.25rem;
}

.switch-card-body p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.section-intro-card {
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.85rem 1.15rem;
  margin-bottom: 0.75rem;
}

/* Question Area */
.questions-pane {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  overflow-y: auto;
  padding: 0 0.4rem 1.5rem 0;
}

.questions-pane > * {
  flex-shrink: 0;
}

.question-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.35rem;
  transition: var(--transition);
  position: relative;
  scroll-margin-top: 0.25rem;
}

.question-card.flagged {
  border-color: var(--warning);
  box-shadow: 0 0 12px rgba(245, 158, 11, 0.2);
}

.question-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1rem;
  gap: 0.5rem;
}

.question-num-badge {
  font-weight: 700;
  font-size: 0.95rem;
  background: rgba(99, 102, 241, 0.2);
  color: #a5b4fc;
  padding: 0.3rem 0.75rem;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.btn-flag {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  gap: 0.3rem;
  transition: var(--transition);
}

.btn-flag:hover, .btn-flag.active {
  background: var(--warning-bg);
  border-color: var(--warning);
  color: var(--warning);
}

.question-stem {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  line-height: 1.6;
  white-space: pre-line;
}

/* Listening QR & Audio Box */
.audio-qr-box {
  background: rgba(99, 102, 241, 0.08);
  border: 1px dashed rgba(99, 102, 241, 0.35);
  border-radius: var(--radius-md);
  padding: 1rem;
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.qr-code-wrapper {
  background: white;
  padding: 6px;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  align-items: center;
}

.qr-code-img {
  width: 90px;
  height: 90px;
  object-fit: contain;
  display: block;
}

.qr-label {
  font-size: 0.7rem;
  color: #334155;
  font-weight: 700;
  margin-top: 4px;
}

.audio-controls-area {
  flex: 1;
  min-width: 200px;
}

.audio-title {
  font-size: 0.9rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  color: #a5b4fc;
}

.audio-btn-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

/* Embedded MP3 Audio Player Box */
.audio-player-box {
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.12) 0%, rgba(168, 85, 247, 0.08) 100%);
  border: 1px solid rgba(99, 102, 241, 0.35);
  border-radius: var(--radius-md);
  padding: 1rem 1.15rem;
  margin-bottom: 1.25rem;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
  transition: var(--transition);
}

.audio-player-box:hover {
  border-color: rgba(99, 102, 241, 0.55);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.15);
}

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

.audio-player-info {
  flex: 1;
  min-width: 200px;
}

.audio-player-info .audio-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: #c7d2fe;
  margin-bottom: 2px;
}

[data-theme="light"] .audio-player-info .audio-title {
  color: #4338ca;
}

.audio-subtitle {
  font-size: 0.78rem;
  color: var(--text-secondary);
}

.audio-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: rgba(99, 102, 241, 0.2);
  color: #a5b4fc;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  border: 1px solid rgba(99, 102, 241, 0.4);
  letter-spacing: 0.03em;
}

.audio-pulse-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--success);
  box-shadow: 0 0 8px var(--success);
  display: inline-block;
  animation: pulseDot 2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.85); }
}

.audio-element-wrapper {
  margin: 0.5rem 0 0.75rem 0;
  width: 100%;
}

.main-audio-player {
  width: 100%;
  height: 42px;
  border-radius: 24px;
  outline: none;
  filter: drop-shadow(0 2px 6px rgba(0, 0, 0, 0.2));
}

.audio-tools-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.audio-playback-helpers {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.audio-tool-btn {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.audio-tool-btn:hover {
  background: rgba(99, 102, 241, 0.25);
  border-color: var(--accent-primary);
  color: #ffffff;
  transform: translateY(-1px);
}

[data-theme="light"] .audio-tool-btn {
  background: rgba(0, 0, 0, 0.04);
}

[data-theme="light"] .audio-tool-btn:hover {
  background: rgba(99, 102, 241, 0.15);
  color: var(--accent-primary);
}

.audio-extra-actions {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.qr-drawer {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px dashed rgba(99, 102, 241, 0.25);
  animation: fadeIn 0.2s ease-out;
}

.qr-drawer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: rgba(255, 255, 255, 0.05);
  padding: 0.75rem;
  border-radius: var(--radius-sm);
  width: fit-content;
  margin: 0 auto;
}

.qr-drawer-inner .qr-code-img {
  width: 100px;
  height: 100px;
  background: #ffffff;
  padding: 4px;
  border-radius: 4px;
}

/* Floating Audio Sticky Controller */
.sticky-audio-controller {
  position: fixed;
  bottom: 1.25rem;
  left: 50%;
  transform: translateX(-50%);
  z-index: 999;
  background: rgba(18, 23, 41, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(99, 102, 241, 0.4);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5), 0 0 20px rgba(99, 102, 241, 0.25);
  border-radius: 999px;
  padding: 0.45rem 1.25rem;
  max-width: 90vw;
  animation: slideUpFade 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

[data-theme="light"] .sticky-audio-controller {
  background: rgba(255, 255, 255, 0.95);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15), 0 0 20px rgba(99, 102, 241, 0.15);
}

@keyframes slideUpFade {
  from { opacity: 0; transform: translate(-50%, 20px); }
  to { opacity: 1; transform: translate(-50%, 0); }
}

.sticky-audio-content {
  display: flex;
  align-items: center;
  gap: 1.15rem;
  flex-wrap: wrap;
}

.sticky-audio-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: #c7d2fe;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 250px;
}

[data-theme="light"] .sticky-audio-info {
  color: #3730a3;
}

.sticky-pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--success);
  box-shadow: 0 0 8px var(--success);
  animation: pulseDot 1.5s infinite;
}

.sticky-audio-actions {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.sticky-btn {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.3rem 0.6rem;
  border-radius: 999px;
  cursor: pointer;
  transition: var(--transition);
}

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

.sticky-btn-play {
  background: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
  padding: 0.3rem 0.75rem;
  font-size: 0.85rem;
}

.sticky-time {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-variant-numeric: tabular-nums;
  margin-left: 0.25rem;
  white-space: nowrap;
}


/* Options List */
.options-list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.option-item {
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
  padding: 0.85rem 1rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  user-select: none;
}

[data-theme="light"] .option-item {
  background: rgba(0, 0, 0, 0.02);
}

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

.option-letter {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  flex-shrink: 0;
  transition: var(--transition);
}

.option-item.selected {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--accent-primary);
}

.option-item.selected .option-letter {
  background: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
}

.option-item.correct {
  background: var(--success-bg) !important;
  border-color: var(--success) !important;
}

.option-item.correct .option-letter {
  background: var(--success) !important;
  color: white;
}

.option-item.incorrect {
  background: var(--error-bg) !important;
  border-color: var(--error) !important;
}

.option-item.incorrect .option-letter {
  background: var(--error) !important;
  color: white;
}

.option-text {
  font-size: 0.95rem;
  line-height: 1.5;
  padding-top: 2px;
}

/* Explanation Box */
.explanation-box {
  margin-top: 1.25rem;
  padding: 1rem 1.25rem;
  background: rgba(16, 185, 129, 0.08);
  border-left: 4px solid var(--success);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  font-size: 0.92rem;
  line-height: 1.6;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Palette Pane */
.palette-pane {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.1rem 1rem;
  overflow-y: auto;
  backdrop-filter: blur(10px);
}

.palette-pane h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.palette-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.legend-dot.answered { background: var(--success); }
.legend-dot.flagged { background: var(--warning); }
.legend-dot.unanswered { background: rgba(255, 255, 255, 0.15); }

/* Palette Section Groups */
.palette-sections {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
}

.palette-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.palette-group-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  padding: 0.35rem 0.55rem;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-color);
  transition: var(--transition);
  user-select: none;
}

.palette-group-header:hover {
  background: rgba(99, 102, 241, 0.15);
  border-color: var(--accent-primary);
}

.palette-group.active .palette-group-header {
  border-color: var(--accent-primary);
  background: rgba(99, 102, 241, 0.18);
}

.palette-group-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-primary);
}

.palette-group-count {
  font-size: 0.72rem;
  font-weight: 700;
  color: #a5b4fc;
  background: rgba(99, 102, 241, 0.2);
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
}

.palette-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.45rem;
}

.palette-btn {
  aspect-ratio: 1;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.85rem;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.palette-btn:hover {
  border-color: var(--accent-primary);
  transform: scale(1.05);
}

.palette-btn.answered {
  background: var(--success-bg);
  border-color: var(--success);
  color: var(--success);
}

.palette-btn.flagged::after {
  content: "";
  position: absolute;
  top: 2px;
  right: 2px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--warning);
}

.palette-btn.current {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* Quiz responsive breakpoints */
@media (max-width: 1279px) {
  .quiz-main-container {
    grid-template-columns: minmax(0, 6fr) minmax(360px, 5fr) 208px;
    gap: 1rem;
    padding: 0.85rem 1rem;
  }
  .passage-pane {
    padding-left: 1.15rem;
  }
  .palette-grid {
    gap: 0.4rem;
  }
}

/* Tablet / phone: single column, normal page scroll */
@media (max-width: 1023px) {
  .section-tabs-wrapper {
    flex-direction: column;
    gap: 0.4rem;
  }
  .section-tab-btn {
    width: 100%;
    padding: 0.45rem 0.75rem;
  }
  .quiz-page {
    height: auto;
    overflow: visible;
  }
  .quiz-page .site-header {
    position: static;
  }
  .quiz-page .header-container {
    flex-wrap: wrap;
  }
  .quiz-topbar {
    position: sticky;
    top: 0;
  }
  .quiz-main-container {
    grid-template-columns: minmax(0, 1fr);
    grid-template-rows: none;
  }
  .questions-pane,
  .palette-pane {
    overflow: visible;
  }
  .questions-pane {
    padding-right: 0;
  }
  .question-card {
    scroll-margin-top: 5.5rem;
  }
  .palette-pane {
    order: -1;
  }
  .passage-pane {
    max-height: 60vh;
  }
  .palette-grid {
    grid-template-columns: repeat(auto-fill, minmax(40px, 1fr));
  }
}

/* Phone: keep the sticky timer bar on one line */
@media (max-width: 600px) {
  .quiz-topbar {
    padding: 0.5rem 0.75rem;
  }
  .quiz-topbar-content {
    flex-wrap: nowrap;
    gap: 0.5rem;
  }
  .quiz-info-group {
    gap: 0.5rem;
    min-width: 0;
  }
  .timer-box {
    font-size: 0.95rem;
    padding: 0.3rem 0.55rem;
  }
  .progress-info {
    font-size: 0.78rem;
  }
  .quiz-topbar .btn-primary {
    padding: 0.45rem 0.8rem !important;
    font-size: 0.82rem;
    white-space: nowrap;
  }
  .question-card {
    scroll-margin-top: 4.5rem;
  }
}

/* Modal Styling */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 1rem;
  opacity: 0;
  pointer-events: none;
  transition: var(--transition);
}

.modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  max-width: 600px;
  width: 100%;
  padding: 2rem;
  box-shadow: var(--shadow-lg);
  position: relative;
  transform: scale(0.95);
  transition: var(--transition);
}

.modal-backdrop.open .modal-card {
  transform: scale(1);
}

.modal-score-circle {
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: var(--accent-gradient);
  margin: 0 auto 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: white;
  box-shadow: 0 8px 24px rgba(99, 102, 241, 0.4);
}

.modal-score-circle .score-num {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1;
}

.modal-score-circle .score-max {
  font-size: 0.85rem;
  opacity: 0.9;
}

.score-stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  text-align: center;
  margin-bottom: 1.5rem;
}

.score-stat-item {
  background: var(--bg-card);
  padding: 0.75rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.score-stat-val {
  font-size: 1.25rem;
  font-weight: 700;
}

.score-stat-lbl {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* Footer */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-color);
  padding: 2rem 1.5rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
  background: var(--bg-secondary);
}