/* ==========================================
   0. FONTS & DESIGN TOKENS
   ========================================== */
@import url('https://fonts.googleapis.com/css2?family=Manrope:wght@500;600;700;800&family=JetBrains+Mono:wght@500;700&family=Cinzel:wght@600;700;800&display=swap');

:root {
  /* surfaces — Middle-earth dark tones */
  --bg: #0D0A07;
  --bg-desktop: #080604;
  --surface: #1A130D;
  --surface-sunken: #110D08;
  --surface-raised: #241B13;
  --border: #3A2C1E;
  --border-strong: #4A3828;

  /* text — warm parchment */
  --text: #E8DCC8;
  --text-dim: #A89880;
  --text-faint: #7A6B5A;

  /* brand accent — One Ring gold */
  --accent: #C9A84C;
  --accent-strong: #D4B95E;
  --accent-soft: #1E1A10;

  /* secondary accent — Elvish green */
  --accent-2: #5B9A6B;
  --accent-2-strong: #4A8A5A;
  --accent-2-soft: #101A14;

  /* status */
  --warn: #D4A24C;
  --danger: #C45C4C;
  --danger-soft: #2A1515;

  /* motion */
  --ease-smooth: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-standard: cubic-bezier(0.4, 0, 0.2, 1);

  /* type */
  --font-display: 'Manrope', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', "SF Mono", Consolas, Monaco, monospace;
  --font-title: 'Cinzel', 'Manrope', serif;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================
   1. RESET & BASE STYLES
   ========================================== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-display);
  background-color: var(--bg); /* Deep dark aesthetic background */
  color: var(--text); /* Soft off-white text for readability */
  line-height: 1.5;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

button {
  font-family: inherit;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 6px;
}

/* ==========================================
   2. APP SHELL LAYOUT (Phone/iPad Focused)
   ========================================== */
.app-shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: 100%;
  position: relative;
}

/* iPad and Mobile Screens Layout Container */
@media screen and (max-width: 1024px) {
  .app-shell {
    width: 100%;
    margin: 0 auto;
    background-color: #0a120d;
  }
}

/* Desktop safety viewport (forces mobile/tablet aspect ratio for testing) */
@media screen and (min-width: 1025px) {
  body {
    background-color: #050906; /* Even darker desktop backdrop */
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
  }
  .app-shell {
    width: 430px;
    height: 932px;
    border-radius: 40px;
    overflow: hidden;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
    background: #0a120d;
    border: 10px solid #1a3020;
  }
}

/* ==========================================
   3. UNIFIED TOP HEADER & NAV
   ========================================== */
.app-header {
  background-color: rgba(16, 28, 20, 0.92); /* Dark green header */
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.45);
  border-bottom: 1px solid var(--border);
}

@media screen and (min-width: 1025px) {
  .app-header {
    position: absolute;
  }
}

/* Brand Bar */
.header-top {
  padding: 16px 20px 10px 20px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.header-title {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--accent); /* Bright vibrant green for dark mode */
  letter-spacing: -0.6px;
  position: relative;
}

/* Top Navigation Links Bar */
.bottom-nav {
  display: flex;
  justify-content: space-around;
  align-items: center;
  padding: 4px 10px 12px 10px;
}

.nav-btn {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: var(--text-faint); /* Muted sage green */
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  transition: color 0.3s var(--ease-smooth), background-color 0.3s var(--ease-smooth), transform 0.15s var(--ease-smooth);
  gap: 4px;
  padding: 8px 0;
  border-radius: 12px;
}

/* Icons styling */
.nav-btn i {
  font-size: 1.3rem;
  transition: transform 0.3s var(--ease-smooth);
}

/* Hover/Active states */
.nav-btn:hover {
  color: var(--text-dim);
}
.nav-btn:active {
  transform: scale(0.94);
}

/* Aesthetic Active State (Pill effect) */
.nav-btn.active {
  color: var(--accent);
  background-color: var(--surface-raised); /* Subtle dark green pill */
}

.nav-btn.active i {
  transform: translateY(-1px) scale(1.05);
}

/* ==========================================
   4. CONTENT MAIN BOX
   ========================================== */
.main-content {
  margin-top: 130px;
  padding: 24px;
  flex: 1;
  overflow-y: auto;
}

/* iPad specific refinements for layout scaling */
@media screen and (min-width: 768px) and (max-width: 1024px) {
  .main-content {
    padding: 40px;
    max-width: 750px;
    margin-left: auto;
    margin-right: auto;
  }
  .header-title {
    font-size: 1.8rem;
  }
  .nav-btn {
    font-size: 0.85rem;
  }
  .nav-btn i {
    font-size: 1.5rem;
  }
}

/* Section switching (drives the Quizz / Learn / Test / Profile tabs) */
.content-section {
  display: none;
}
.content-section.active {
  display: block;
  animation: fadeInSection 0.4s var(--ease-smooth);
}
@keyframes fadeInSection {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
.hidden {
  display: none !important;
}

/* ==========================================
   5. QUIZ HEADER & CATEGORY SCROLL
   ========================================== */
.quiz-header {
  padding: 0 0 16px;
}
.quiz-header h2 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 4px;
  letter-spacing: -0.3px;
}
.quiz-header p {
  font-size: 0.9rem;
  color: var(--text-dim);
}

/* Reusable small uppercase label used above section titles */
.section-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--accent);
  margin-bottom: 6px;
  display: block;
}

/* Horizontal Scroll Menu (Pills) */
.quiz-category-nav {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  padding: 0 0 20px 0;
  scrollbar-width: none;
}
.quiz-category-nav::-webkit-scrollbar {
  display: none;
}

.cat-btn {
  background-color: transparent;
  border: 1.5px solid var(--border-strong);
  padding: 8px 18px;
  border-radius: 24px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
  cursor: pointer;
  white-space: nowrap;
  transition: border-color 0.3s var(--ease-smooth), color 0.3s var(--ease-smooth), background-color 0.3s var(--ease-smooth), box-shadow 0.3s var(--ease-smooth), transform 0.2s var(--ease-smooth);
}
.cat-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}
.cat-btn:active {
  transform: translateY(0) scale(0.97);
}
.cat-btn.active {
  background-color: var(--accent);
  border-color: var(--accent);
  color: #0D0A07;
  box-shadow: 0 6px 14px rgba(201, 168, 76, 0.25);
}

/* ==========================================
   5b. REFERENCE — dual-tile chooser (ApexLearn / Beginner Developer)
   ========================================== */
.reference-header {
  padding: 4px 0 22px;
}
.reference-title {
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.5px;
  margin-bottom: 16px;
}

.reference-tiles {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.reference-tile {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 14px;
  text-align: left;
  background-color: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 18px;
  padding: 16px;
  cursor: pointer;
  overflow: hidden;
  transition: border-color 0.3s var(--ease-smooth), transform 0.3s var(--ease-smooth), box-shadow 0.3s var(--ease-smooth);
}
.reference-tile::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--accent-track, var(--accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease-smooth);
}
.reference-tile[data-ref="beginnerdev"] {
  --accent-track: var(--accent-2);
}
.reference-tile:hover {
  border-color: var(--border-strong);
  transform: translateY(-2px);
}
.reference-tile.active {
  border-color: var(--accent-track, var(--accent));
  box-shadow: 0 10px 26px -12px rgba(0, 0, 0, 0.5);
}
.reference-tile.active::before {
  transform: scaleX(1);
}

.reference-tile-icon {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  background-color: var(--surface-raised);
  color: var(--accent);
  flex-shrink: 0;
  transition: background-color 0.3s var(--ease-smooth), color 0.3s var(--ease-smooth);
}
.reference-tile[data-ref="beginnerdev"] .reference-tile-icon {
  background-color: var(--accent-2-soft);
  color: var(--accent-2);
}

.reference-tile-text {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
  width: 100%;
}
.reference-tile-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.reference-tile-meta {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-faint);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.reference-tile.active .reference-tile-meta {
  color: var(--text-dim);
}

.reference-tile-arrow {
  position: absolute;
  top: 16px;
  right: 14px;
  font-size: 1rem;
  color: var(--text-faint);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.3s var(--ease-smooth), transform 0.3s var(--ease-smooth);
}
.reference-tile.active .reference-tile-arrow {
  opacity: 1;
  transform: translateX(0);
  color: var(--accent-track, var(--accent));
}

.reference-panel {
  display: none;
}
.reference-panel.active {
  display: block;
  animation: fadeInSection 0.35s var(--ease-smooth);
}

.reference-empty-state {
  background-color: var(--surface);
  border: 1.5px dashed var(--border-strong);
  border-radius: 20px;
  padding: 48px 24px;
  text-align: center;
}
.reference-empty-icon {
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background-color: var(--accent-2-soft);
  color: var(--accent-2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin: 0 auto 18px;
}
.reference-empty-state h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
}
.reference-empty-state p {
  font-size: 0.85rem;
  color: var(--text-dim);
  line-height: 1.6;
  max-width: 320px;
  margin: 0 auto;
}

/* ==========================================
   6. QUIZ SETUP CARD
   ========================================== */
.quiz-card {
  background-color: var(--surface);
  border-radius: 20px;
  margin: 0 0 30px;
  padding: 24px;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  border: 1px solid var(--border);
  transition: transform 0.35s var(--ease-smooth), opacity 0.3s var(--ease-smooth), box-shadow 0.35s var(--ease-smooth);
}
.quiz-card:hover {
  box-shadow: 0 16px 36px -12px rgba(0, 0, 0, 0.5);
}

.card-badge {
  display: inline-block;
  background-color: var(--surface-raised);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 12px;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

.card-title {
  font-size: 1.3rem;
  font-weight: 700;
  color: #E8DCC8;
  margin-bottom: 10px;
  line-height: 1.3;
}

.card-desc {
  color: #A89880;
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 20px;
}

.length-options {
  display: flex;
  gap: 8px;
  margin-bottom: 4px;
  flex-wrap: wrap;
}

.length-btn {
  background-color: var(--bg);
  border: 1.5px solid var(--border);
  color: var(--text-dim);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 7px 14px;
  border-radius: 10px;
  cursor: pointer;
  transition: border-color 0.25s var(--ease-smooth), color 0.25s var(--ease-smooth), background-color 0.25s var(--ease-smooth), transform 0.2s var(--ease-smooth);
}
.length-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.length-btn:active {
  transform: scale(0.96);
}
.length-btn.active {
  background-color: var(--text);
  border-color: var(--text);
  color: var(--bg);
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-top: 1px solid #3A2C1E;
  padding-top: 20px;
  margin-top: 20px;
}

.author-info {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  color: #7A6B5A;
  font-weight: 600;
}

.avatar {
  width: 32px;
  height: 32px;
  background: #142b1d;
  color: #C9A84C;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
}

.start-btn {
  background: linear-gradient(135deg, #0fa958 0%, #0d964d 100%);
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(15, 169, 88, 0.2);
  transition: transform 0.2s var(--ease-smooth), box-shadow 0.2s var(--ease-smooth), opacity 0.2s var(--ease-smooth);
}
.start-btn:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(15, 169, 88, 0.28);
}
.start-btn:active {
  transform: translateY(1px);
  box-shadow: 0 2px 6px rgba(15, 169, 88, 0.2);
}
.start-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
}

.secondary-btn {
  background-color: #111f16;
  color: #E8DCC8;
  border: 1.5px solid #243d2d;
  padding: 10px 18px;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all 0.2s ease;
}
.secondary-btn:hover {
  border-color: #C9A84C;
  color: #C9A84C;
}
.secondary-btn:active {
  transform: translateY(1px);
}

/* ==========================================
   7. QUIZ GAME (active question flow)
   ========================================== */
.quiz-game {
  padding-bottom: 10px;
}

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

.exit-btn {
  background-color: #142b1d;
  border: none;
  color: #A89880;
  width: 34px;
  height: 34px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  cursor: pointer;
  flex-shrink: 0;
  transition: background-color 0.2s ease;
}
.exit-btn:hover {
  background-color: #3A2C1E;
}

.progress-bar-track {
  flex: 1;
  height: 8px;
  background-color: #3A2C1E;
  border-radius: 8px;
  overflow: hidden;
}
.progress-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(135deg, #0fa958 0%, #0d964d 100%);
  border-radius: 8px;
  transition: width 0.3s ease;
}

.score-pill, .timer-pill {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 6px 12px;
  border-radius: 10px;
  white-space: nowrap;
  flex-shrink: 0;
  transition: background-color 0.3s var(--ease-smooth), color 0.3s var(--ease-smooth);
}
.score-pill {
  background-color: var(--surface-raised);
  color: var(--accent);
}
.timer-pill {
  background-color: #332112;
  color: var(--warn);
  display: inline-flex;
  align-items: center;
  gap: 5px;
}
.timer-pill i {
  font-size: 0.85rem;
}
.timer-pill.timer-low {
  background-color: var(--danger-soft);
  color: var(--danger);
  animation: timerPulse 1s var(--ease-standard) infinite;
}
@keyframes timerPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

.question-meta {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-faint);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 10px;
}

.question-card {
  background-color: var(--surface);
  border-radius: 20px;
  padding: 22px;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  border: 1px solid var(--border);
  margin-bottom: 16px;
  animation: fadeInSection 0.3s var(--ease-smooth);
}

.question-text {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
  margin-bottom: 20px;
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  text-align: left;
  background-color: var(--surface-sunken);
  border: 1.5px solid var(--border);
  border-radius: 14px;
  padding: 12px 14px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.2s var(--ease-smooth), background-color 0.2s var(--ease-smooth), transform 0.2s var(--ease-smooth), opacity 0.25s var(--ease-smooth);
}
.option-btn:hover:not(:disabled) {
  border-color: var(--accent);
  background-color: var(--surface-raised);
  transform: translateX(2px);
}
.option-letter {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background-color: #1a3325;
  color: var(--text-dim);
  font-size: 0.8rem;
  font-weight: 700;
  font-family: var(--font-mono);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background-color 0.2s var(--ease-smooth), color 0.2s var(--ease-smooth);
}
.option-btn:disabled {
  cursor: default;
}
.option-btn.selected {
  border-color: #C9A84C;
  background-color: #142b1d;
}
.option-btn.correct {
  border-color: #C9A84C;
  background-color: #10331d;
}
.option-btn.correct .option-letter {
  background-color: #C9A84C;
  color: #0a120d;
}
.option-btn.incorrect {
  border-color: #d64545;
  background-color: #3b1717;
}
.option-btn.incorrect .option-letter {
  background-color: #d64545;
  color: #ffffff;
}
.option-btn.faded {
  opacity: 0.55;
}

.explanation-box {
  margin-top: 16px;
  padding: 14px 16px;
  border-radius: 14px;
  background-color: var(--surface-sunken);
  border: 1px solid var(--border);
  animation: fadeInSection 0.3s var(--ease-smooth);
}
.explanation-label {
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 6px;
  color: #C9A84C;
}
.explanation-label.wrong {
  color: #f26868;
}
.explanation-box p {
  font-size: 0.85rem;
  color: #A89880;
  line-height: 1.5;
}

.next-btn {
  width: 100%;
  background: linear-gradient(135deg, #0fa958 0%, #0d964d 100%);
  color: white;
  border: none;
  padding: 14px 20px;
  border-radius: 14px;
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(15, 169, 88, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: transform 0.2s var(--ease-smooth), box-shadow 0.2s var(--ease-smooth);
  animation: fadeInSection 0.25s var(--ease-smooth);
}
.next-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(15, 169, 88, 0.28);
}
.next-btn:active {
  transform: translateY(1px);
}

/* ==========================================
   8. RESULTS SCREEN
   ========================================== */
.quiz-results {
  padding-top: 10px;
}
.result-card {
  background-color: var(--surface);
  border-radius: 20px;
  padding: 32px 24px;
  text-align: center;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  border: 1px solid var(--border);
  animation: fadeInSection 0.4s var(--ease-smooth);
}
.result-score {
  font-family: var(--font-mono);
  font-size: 3rem;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 8px;
}
.result-score.mid {
  color: #e59a4c;
}
.result-score.low {
  color: #d64545;
}
.result-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  color: #E8DCC8;
  margin-bottom: 6px;
}
.result-card p {
  font-size: 0.9rem;
  color: #A89880;
  margin-bottom: 22px;
}
.result-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
}

.section-breakdown {
  text-align: left;
  margin-bottom: 22px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.breakdown-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.breakdown-name {
  flex: 1;
  font-size: 0.8rem;
  font-weight: 600;
  color: #A89880;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.breakdown-track {
  flex: 1.4;
  height: 8px;
  border-radius: 8px;
  background-color: #3A2C1E;
  overflow: hidden;
}
.breakdown-fill {
  height: 100%;
  background: linear-gradient(135deg, #0fa958 0%, #0d964d 100%);
  border-radius: 8px;
}
.breakdown-pct {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: #7A6B5A;
  width: 38px;
  text-align: right;
  flex-shrink: 0;
}

/* ==========================================
   9. LEARN — CHAPTER STUDY GUIDE (accordion)
   ========================================== */
.learn-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}
.learn-toolbar-stat {
  font-size: 0.8rem;
  font-weight: 600;
  color: #7A6B5A;
}
.learn-toggle-all-btn {
  background: none;
  border: 1.5px solid #243d2d;
  color: #A89880;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 6px 14px;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.2s ease;
}
.learn-toggle-all-btn:hover {
  border-color: #C9A84C;
  color: #C9A84C;
}

.chapter-summary-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 24px;
}

.chapter-summary-card {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  overflow: hidden;
  transition: border-color 0.3s var(--ease-smooth), transform 0.3s var(--ease-smooth);
}
.chapter-summary-card:hover {
  transform: translateY(-1px);
}
.chapter-summary-card.open {
  border-color: #24462f;
}

.chapter-summary-header {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 14px;
  background: none;
  border: none;
  padding: 18px;
  cursor: pointer;
  text-align: left;
}

.chapter-summary-icon {
  width: 42px;
  height: 42px;
  border-radius: 13px;
  background-color: #142b1d;
  color: #C9A84C;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.chapter-summary-heading {
  flex: 1;
  min-width: 0;
}
.chapter-summary-eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: var(--accent);
  margin-bottom: 2px;
}
.chapter-summary-heading h3 {
  font-size: 1rem;
  font-weight: 700;
  color: #E8DCC8;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chapter-summary-score {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 700;
  color: #7A6B5A;
  background-color: #0a120d;
  border: 1px solid #3A2C1E;
  padding: 4px 9px;
  border-radius: 10px;
  flex-shrink: 0;
  white-space: nowrap;
  transition: color 0.25s var(--ease-smooth), border-color 0.25s var(--ease-smooth);
}
.chapter-summary-score.high {
  color: #C9A84C;
  border-color: #1e4b30;
}
.chapter-summary-score.mid {
  color: #e59a4c;
  border-color: #4b3a1e;
}
.chapter-summary-score.low {
  color: #f26868;
  border-color: #4b1e1e;
}

.chapter-summary-chevron {
  color: #7A6B5A;
  font-size: 1.1rem;
  flex-shrink: 0;
  transition: transform 0.4s var(--ease-smooth), color 0.3s var(--ease-smooth);
}
.chapter-summary-card.open .chapter-summary-chevron {
  transform: rotate(180deg);
  color: #C9A84C;
}

.chapter-summary-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s var(--ease-smooth);
}
.chapter-summary-card.open .chapter-summary-body {
  max-height: 4000px;
}

.chapter-summary-inner {
  padding: 0 18px 20px;
  border-top: 1px solid #3A2C1E;
  padding-top: 16px;
}

.chapter-summary-intro {
  font-size: 0.85rem;
  color: #A89880;
  line-height: 1.6;
  margin-bottom: 18px;
}

.chapter-topic {
  margin-bottom: 18px;
}
.chapter-topic:last-of-type {
  margin-bottom: 20px;
}
.chapter-topic h4 {
  font-size: 0.82rem;
  font-weight: 800;
  color: #E8DCC8;
  margin-bottom: 8px;
  letter-spacing: 0.1px;
}
.chapter-topic-intro {
  font-size: 0.82rem;
  color: #A89880;
  margin-bottom: 8px;
  line-height: 1.5;
}

.chapter-point-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.chapter-point {
  display: flex;
  gap: 10px;
  align-items: flex-start;
}
.chapter-point-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: #C9A84C;
  margin-top: 7px;
  flex-shrink: 0;
}
.chapter-point-text {
  font-size: 0.85rem;
  color: #A89880;
  line-height: 1.55;
}
.chapter-point-text strong {
  color: #E8DCC8;
  font-weight: 700;
}

.chapter-code-block {
  margin-top: 6px;
  background-color: #0a120d;
  border: 1px solid #3A2C1E;
  border-radius: 10px;
  padding: 10px 12px;
  font-family: "SF Mono", Consolas, Monaco, monospace;
  font-size: 0.78rem;
  color: #7fd4a3;
  white-space: pre-wrap;
  word-break: break-word;
  line-height: 1.5;
}

.chapter-quiz-cta {
  width: 100%;
  background-color: #0a120d;
  border: 1.5px solid #C9A84C;
  color: #C9A84C;
  padding: 13px;
  border-radius: 14px;
  font-weight: 700;
  font-size: 0.88rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: background-color 0.2s ease;
}
.chapter-quiz-cta:hover {
  background-color: #142b1d;
}
.chapter-quiz-cta:active {
  transform: translateY(1px);
}

.exam-cta {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 14px;
  background: linear-gradient(135deg, #142b1d 0%, #0f2117 100%);
  border: 1px solid #3A2C1E;
  border-radius: 18px;
  padding: 16px 18px;
  cursor: pointer;
  text-align: left;
  transition: border-color 0.3s var(--ease-smooth), transform 0.3s var(--ease-smooth);
}
.exam-cta:hover {
  border-color: #C9A84C;
  transform: translateY(-1px);
}
.exam-cta:active {
  transform: scale(0.99);
}
.exam-cta-icon {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background-color: #0a120d;
  color: #C9A84C;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
}
.exam-cta-text {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.exam-cta-text strong {
  font-size: 0.9rem;
  color: #E8DCC8;
  font-weight: 700;
}
.exam-cta-text span {
  font-size: 0.78rem;
  color: #A89880;
}
.exam-cta > i {
  color: #7A6B5A;
  font-size: 1.1rem;
}

/* ==========================================
   10. PROFILE / STATS
   ========================================== */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 28px;
}
.stat-card {
  background-color: var(--surface);
  border-radius: 16px;
  padding: 18px;
  border: 1px solid var(--border);
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  transition: transform 0.3s var(--ease-smooth);
}
.stat-card:hover {
  transform: translateY(-2px);
}
.stat-value {
  font-family: var(--font-mono);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 4px;
}
.stat-label {
  font-size: 0.78rem;
  color: #7A6B5A;
  font-weight: 600;
}

.section-subtitle {
  font-size: 1rem;
  font-weight: 700;
  color: #E8DCC8;
  margin-bottom: 14px;
}

.category-progress {
  background-color: #111f16;
  border-radius: 16px;
  padding: 18px;
  border: 1px solid #3A2C1E;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  margin-bottom: 24px;
}

.progress-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}
.progress-row:last-child {
  margin-bottom: 0;
}
.progress-name {
  flex: 1.1;
  font-size: 0.82rem;
  font-weight: 600;
  color: #A89880;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.progress-track {
  flex: 1.6;
  height: 8px;
  border-radius: 8px;
  background-color: #3A2C1E;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(135deg, #0fa958 0%, #0d964d 100%);
  border-radius: 8px;
  transition: width 0.5s var(--ease-smooth);
}
.progress-pct {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 700;
  color: #7A6B5A;
  width: 38px;
  text-align: right;
  flex-shrink: 0;
}
.progress-empty {
  font-size: 0.85rem;
  color: #7A6B5A;
}

.reset-btn {
  width: 100%;
  background-color: #2b1111;
  color: #f26868;
  border: 1px solid #4a1d1d;
  padding: 14px;
  border-radius: 14px;
  font-weight: 700;
  font-size: 0.9rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: background-color 0.2s ease;
}
.reset-btn:hover {
  background-color: #3b1717;
}

/* ==========================================
   11. SHARED EMPTY / LOADING STATE
   ========================================== */
.empty-state {
  text-align: center;
  padding: 40px 20px;
  color: #7A6B5A;
  font-size: 0.9rem;
}

/* ==========================================
   12. GUIDE — SPACED REPETITION (SRS)
   ========================================== */

/* Controls row */
.guide-controls {
  display: flex;
  align-items: flex-end;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.guide-setting {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.guide-setting label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-faint);
}

.guide-setting input {
  width: 80px;
  padding: 8px 10px;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  background-color: var(--surface-sunken);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  outline: none;
  transition: border-color 0.25s var(--ease-smooth);
}

.guide-setting input:focus {
  border-color: var(--accent);
}

.guide-start-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

/* Chapter filter pills */
.chapter-filter {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding-bottom: 8px;
  scrollbar-width: none;
}
.chapter-filter::-webkit-scrollbar {
  display: none;
}

.chapter-pill {
  background-color: transparent;
  border: 1.5px solid var(--border-strong);
  padding: 7px 14px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-dim);
  cursor: pointer;
  white-space: nowrap;
  transition: border-color 0.3s var(--ease-smooth), color 0.3s var(--ease-smooth), background-color 0.3s var(--ease-smooth), transform 0.2s var(--ease-smooth);
}
.chapter-pill:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
}
.chapter-pill:active {
  transform: translateY(0) scale(0.97);
}
.chapter-pill.active {
  background-color: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
  box-shadow: 0 4px 10px rgba(18, 199, 102, 0.2);
}

/* SRS card */
.guide-progress-bar {
  height: 6px;
  background-color: var(--border);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 6px;
}
.guide-progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(135deg, #0fa958 0%, #0d964d 100%);
  border-radius: 6px;
  transition: width 0.3s var(--ease-smooth);
}

.guide-progress-text {
  text-align: right;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-faint);
  margin-bottom: 14px;
}

.srs-card {
  background-color: var(--surface);
  border-radius: 20px;
  padding: 24px;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  border: 1px solid var(--border);
  margin-bottom: 14px;
  animation: fadeInSection 0.25s var(--ease-smooth);
}

.srs-card-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
}

.srs-card-heading {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-faint);
}

.srs-card-body {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.6;
}

.srs-card-body .cloze-blank {
  display: inline-block;
  min-width: 60px;
  border-bottom: 2px solid var(--accent);
  text-align: center;
  color: var(--accent);
  font-weight: 800;
  padding: 0 4px;
}

.srs-card-body .cloze-reveal {
  background-color: var(--accent-soft);
  color: var(--accent);
  font-weight: 800;
  padding: 2px 6px;
  border-radius: 6px;
}

.srs-card-body .reverse-front {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--accent);
  text-align: center;
  margin-bottom: 14px;
}

.srs-card-body .reverse-divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 14px 0;
}

.srs-card-body .reverse-back {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-dim);
  line-height: 1.5;
}

.srs-card-body .reverse-back .cloze-reveal {
  background-color: var(--accent-soft);
  color: var(--accent);
  font-weight: 800;
}

.srs-card-extra {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-dim);
  line-height: 1.5;
}

/* Show answer button */
.srs-show-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

/* Grade buttons */
.srs-grade-buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-bottom: 10px;
}

.btn-grade {
  border: none;
  border-radius: 12px;
  padding: 12px 4px;
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  cursor: pointer;
  color: #0a120d;
  transition: transform 0.2s var(--ease-smooth), box-shadow 0.2s var(--ease-smooth);
}
.btn-grade:active {
  transform: translateY(1px) scale(0.97);
}

.btn-grade-again {
  background-color: var(--danger);
}
.btn-grade-again:hover {
  box-shadow: 0 4px 12px rgba(242, 104, 104, 0.3);
}

.btn-grade-hard {
  background-color: var(--warn);
}
.btn-grade-hard:hover {
  box-shadow: 0 4px 12px rgba(229, 154, 76, 0.3);
}

.btn-grade-good {
  background-color: var(--accent);
}
.btn-grade-good:hover {
  box-shadow: 0 4px 12px rgba(18, 199, 102, 0.3);
}

.btn-grade-easy {
  background-color: var(--accent-2);
}
.btn-grade-easy:hover {
  box-shadow: 0 4px 12px rgba(76, 158, 229, 0.3);
}

.guide-again-color { color: var(--danger) !important; }
.guide-hard-color { color: var(--warn) !important; }
.guide-good-color { color: var(--accent) !important; }
.guide-easy-color { color: var(--accent-2) !important; }

/* Edit row */
.srs-edit-row {
  text-align: center;
  margin-bottom: 8px;
}

.srs-edit-form {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 14px;
  margin-bottom: 10px;
  animation: fadeInSection 0.2s var(--ease-smooth);
}

.srs-edit-form textarea {
  width: 100%;
  min-height: 70px;
  padding: 10px 12px;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  background-color: var(--surface-sunken);
  color: var(--text);
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  resize: vertical;
  outline: none;
  transition: border-color 0.25s var(--ease-smooth);
}

.srs-edit-form textarea:focus {
  border-color: var(--accent);
}

.edit-form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
  margin-top: 10px;
}

/* Summary icon */
.guide-summary-icon {
  font-size: 2.5rem;
  color: var(--accent);
  margin-bottom: 10px;
}

/* ==========================================
   13. HEATMAP (Profile tab)
   ========================================== */
.heatmap-section {
  background-color: var(--surface);
  border-radius: 16px;
  padding: 18px;
  border: 1px solid var(--border);
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.4);
  margin-bottom: 16px;
}

.heatmap-legend {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 4px;
  margin-bottom: 10px;
}

.heatmap-legend-label {
  font-size: 0.65rem;
  font-weight: 600;
  color: var(--text-faint);
  margin: 0 2px;
}

.heatmap-cell {
  width: 11px;
  height: 11px;
  border-radius: 2px;
  background-color: var(--border);
}

.heatmap-cell[data-level="1"] { background-color: rgba(18, 199, 102, 0.25); }
.heatmap-cell[data-level="2"] { background-color: rgba(18, 199, 102, 0.45); }
.heatmap-cell[data-level="3"] { background-color: rgba(18, 199, 102, 0.65); }
.heatmap-cell[data-level="4"] { background-color: rgba(18, 199, 102, 0.9); }

.heatmap-grid {
  display: grid;
  grid-template-rows: repeat(7, 1fr);
  grid-auto-flow: column;
  gap: 3px;
  overflow-x: auto;
  scrollbar-width: none;
}
.heatmap-grid::-webkit-scrollbar {
  display: none;
}