/* Variables CSS */
:root {
  --blue:    #2563eb;
  --blue2:   #1d4ed8;
  --blue3:   #eff6ff;
  --blue4:   #dbeafe;
  --ink:     #111827;
  --ink2:    #374151;
  --ink3:    #6b7280;
  --ink4:    #9ca3af;
  --bg:      #f9fafb;
  --white:   #ffffff;
  --border:  #e5e7eb;
  --border2: #f3f4f6;
  --green:   #059669;
  --green2:  #d1fae5;
  --orange:  #f59e0b;
  --orange2: #fef3c7;
  --red:     #dc2626;
  --red2:    #fee2e2;
  --radius:  12px;
  --radius2: 8px;
  --shadow:  0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
  --shadow2: 0 4px 16px rgba(0,0,0,.08), 0 2px 6px rgba(0,0,0,.05);
  --shadow3: 0 10px 40px rgba(37,99,235,.15);
}

*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Plus Jakarta Sans', sans-serif;
  background: var(--bg);
  color: var(--ink);
  overflow-x: clip;
  -webkit-font-smoothing: antialiased;
}

/* NAVBAR */
nav {
  position: fixed; top:0; left:0; right:0; z-index:200;
  height: 64px;
  background: rgba(255,255,255,.95);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(10px);
  display: flex; align-items: center;
  padding: 0 2rem;
  gap: 1rem;
}
.nav-logo { font-size: 1.2rem; font-weight: 800; color: var(--ink); text-decoration: none; letter-spacing: -.02em; margin-right: auto; }
.nav-logo span { color: var(--blue); }
.nav-badge { background: var(--blue3); color: var(--blue2); font-size: .72rem; font-weight: 700; padding: .3rem .75rem; border-radius: 20px; letter-spacing: .01em; }
.nav-links { display:flex; gap:1.5rem; list-style:none; align-items:center; }
.nav-links a { font-size: .875rem; font-weight: 500; color: var(--ink3); text-decoration: none; transition: color .15s; }
.nav-links a:hover { color: var(--ink); }
.nav-links a.active { color: var(--blue); font-weight: 600; }
.nav-cta { background: var(--blue); color: #fff !important; padding: .5rem 1.25rem; border-radius: 8px; font-weight: 700 !important; font-size: .875rem !important; transition: background .15s, transform .15s; display: inline-flex; align-items: center; min-height: 44px; }
.nav-cta:hover { background: var(--blue2) !important; transform: translateY(-1px); }

/* PAGE CONTENT */
.page-wrap {
  padding-top: 64px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* QUIZ HERO */
.quiz-hero {
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 60%, #3b82f6 100%);
  padding: 4rem 2rem 3rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.quiz-hero::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(255,255,255,.07) 0%, transparent 70%);
  pointer-events: none;
}
.quiz-hero-inner { max-width: 680px; margin: 0 auto; position: relative; }
.quiz-hero-badge {
  display: inline-flex; align-items: center; gap: .45rem;
  background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.25);
  color: #fff; font-size: .75rem; font-weight: 700;
  padding: .35rem .875rem; border-radius: 20px;
  letter-spacing: .04em; text-transform: uppercase;
  margin-bottom: 1.5rem;
}
.quiz-hero h1 {
  font-size: clamp(2rem, 4vw, 2.8rem);
  font-weight: 800; color: #fff;
  line-height: 1.2; letter-spacing: -.03em;
  margin-bottom: 1rem;
}
.quiz-hero p {
  font-size: 1rem; color: rgba(255,255,255,.8);
  line-height: 1.75; max-width: 500px; margin: 0 auto 2rem;
}

/* SCREENS */
.screen { display: none; }
.screen.active { display: block; }

/* START SCREEN */
.quiz-start {
  max-width: 900px;
  margin: 3rem auto;
  padding: 0 2rem;
}
.quiz-start-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 3rem;
  box-shadow: var(--shadow2);
  text-align: center;
}
.quiz-start-icon {
  width: 80px; height: 80px;
  background: var(--blue3);
  border-radius: 18px;
  display: flex; align-items: center; justify-content: center;
  font-size: 2.5rem;
  margin: 0 auto 1.5rem;
}
.quiz-start-card h2 {
  font-size: 1.75rem; font-weight: 800; color: var(--ink);
  letter-spacing: -.02em; margin-bottom: .75rem;
}
.quiz-start-card p {
  font-size: .95rem; color: var(--ink3); line-height: 1.7;
  margin-bottom: 2.5rem; max-width: 500px; margin-left: auto; margin-right: auto;
}
.quiz-features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2.5rem;
  text-align: left;
}
.quiz-feature {
  padding: 1.25rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.quiz-feature-icon {
  font-size: 1.5rem;
  margin-bottom: .5rem;
}
.quiz-feature-title {
  font-size: .875rem;
  font-weight: 700;
  color: var(--ink);
  margin-bottom: .25rem;
}
.quiz-feature-desc {
  font-size: .8rem;
  color: var(--ink3);
  line-height: 1.5;
}
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  background: var(--blue);
  color: #fff;
  font-size: 1rem;
  font-weight: 700;
  padding: 1rem 2.5rem;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all .15s;
  box-shadow: var(--shadow2);
}
.btn-primary:hover {
  background: var(--blue2);
  transform: translateY(-2px);
  box-shadow: var(--shadow3);
}

/* QUIZ SCREEN */
.quiz-container {
  max-width: 800px;
  margin: 2rem auto 4rem;
  padding: 0 1.5rem;
}
.quiz-progress-bar {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}
.quiz-progress-fill-wrap {
  flex: 1;
  height: 8px;
  background: var(--border2);
  border-radius: 10px;
  overflow: hidden;
}
.quiz-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--blue), var(--blue2));
  transition: width .3s ease;
  width: 0%;
}
.quiz-progress-text {
  font-size: .875rem;
  font-weight: 700;
  color: var(--ink2);
  white-space: nowrap;
}
.quiz-question-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 2.5rem;
  box-shadow: var(--shadow2);
  margin-bottom: 1.5rem;
}
.quiz-question-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border2);
}
.quiz-question-num {
  font-size: .85rem;
  font-weight: 700;
  color: var(--blue);
  background: var(--blue3);
  padding: .4rem .875rem;
  border-radius: 20px;
}
.quiz-question-chapter {
  font-size: .8rem;
  font-weight: 600;
  color: var(--ink3);
}
.quiz-question-text {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.7;
  margin-bottom: 2rem;
}
.quiz-answers {
  display: flex;
  flex-direction: column;
  gap: .875rem;
  margin-bottom: 2rem;
}
.quiz-answer {
  padding: 1.125rem 1.25rem;
  background: var(--bg);
  border: 2px solid var(--border);
  border-radius: var(--radius);
  font-size: .95rem;
  font-weight: 500;
  color: var(--ink2);
  cursor: pointer;
  transition: all .15s;
  display: flex;
  align-items: center;
  gap: .75rem;
}
.quiz-answer:hover {
  border-color: var(--blue);
  background: var(--blue3);
}
.quiz-answer.selected {
  border-color: var(--blue);
  background: var(--blue3);
  color: var(--blue2);
  font-weight: 600;
}
.quiz-answer.correct {
  border-color: var(--green);
  background: var(--green2);
  color: var(--green);
  font-weight: 600;
}
.quiz-answer.wrong {
  border-color: var(--red);
  background: var(--red2);
  color: var(--red);
  font-weight: 600;
}
.quiz-answer.disabled {
  pointer-events: none;
  opacity: 0.6;
}
.quiz-answer-letter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--white);
  border-radius: 6px;
  font-size: .8rem;
  font-weight: 700;
  color: var(--ink3);
  flex-shrink: 0;
}
.quiz-answer.selected .quiz-answer-letter {
  background: var(--blue);
  color: #fff;
}
.quiz-answer.correct .quiz-answer-letter {
  background: var(--green);
  color: #fff;
}
.quiz-answer.wrong .quiz-answer-letter {
  background: var(--red);
  color: #fff;
}
.quiz-hint-box {
  background: var(--orange2);
  border-left: 4px solid var(--orange);
  padding: 1rem 1.25rem;
  border-radius: var(--radius2);
  margin-top: 1.5rem;
  display: none;
}
.quiz-hint-box.visible {
  display: block;
}
.quiz-hint-title {
  font-size: .8rem;
  font-weight: 700;
  color: #92400e;
  margin-bottom: .5rem;
}
.quiz-hint-text {
  font-size: .875rem;
  color: #78350f;
  line-height: 1.6;
}
.quiz-explanation-box {
  background: var(--blue3);
  border-left: 4px solid var(--blue);
  padding: 1rem 1.25rem;
  border-radius: var(--radius2);
  margin-top: 1rem;
  display: none;
}
.quiz-explanation-box.visible {
  display: block;
}
.quiz-explanation-title {
  font-size: .8rem;
  font-weight: 700;
  color: var(--blue2);
  margin-bottom: .5rem;
}
.quiz-explanation-text {
  font-size: .875rem;
  color: var(--blue2);
  line-height: 1.6;
}
.quiz-actions {
  display: flex;
  gap: .875rem;
  justify-content: space-between;
}
.btn-secondary {
  padding: .875rem 1.5rem;
  background: var(--white);
  border: 2px solid var(--border);
  color: var(--ink2);
  font-size: .875rem;
  font-weight: 600;
  border-radius: var(--radius2);
  cursor: pointer;
  transition: all .15s;
}
.btn-secondary:hover {
  border-color: var(--ink3);
  background: var(--bg);
}
.btn-hint {
  padding: .875rem 1.5rem;
  background: var(--orange2);
  border: 2px solid var(--orange);
  color: #92400e;
  font-size: .875rem;
  font-weight: 600;
  border-radius: var(--radius2);
  cursor: pointer;
  transition: all .15s;
}
.btn-hint:hover {
  background: var(--orange);
  color: #fff;
}
.btn-hint:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.btn-next {
  padding: .875rem 2rem;
  background: var(--blue);
  border: none;
  color: #fff;
  font-size: .875rem;
  font-weight: 700;
  border-radius: var(--radius2);
  cursor: pointer;
  transition: all .15s;
  margin-left: auto;
}
.btn-next:hover {
  background: var(--blue2);
  transform: translateY(-1px);
}
.btn-next:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* RESULTS SCREEN */
.quiz-results {
  max-width: 900px;
  margin: 2rem auto 4rem;
  padding: 0 1.5rem;
}
.quiz-results-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 3rem;
  box-shadow: var(--shadow2);
  text-align: center;
  margin-bottom: 2rem;
}
.quiz-results-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
}
.quiz-results-title {
  font-size: 2rem;
  font-weight: 800;
  color: var(--ink);
  margin-bottom: .5rem;
}
.quiz-results-score {
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--blue);
  margin: 1.5rem 0;
  line-height: 1;
}
.quiz-results-score span {
  font-size: 2rem;
  color: var(--ink3);
}
.quiz-results-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1.25rem;
  margin: 2rem 0;
}
.quiz-results-stat {
  padding: 1.25rem;
  background: var(--bg);
  border-radius: var(--radius);
}
.quiz-results-stat-value {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--ink);
  margin-bottom: .25rem;
}
.quiz-results-stat-label {
  font-size: .8rem;
  font-weight: 600;
  color: var(--ink3);
  text-transform: uppercase;
  letter-spacing: .04em;
}
.quiz-results-stat.correct .quiz-results-stat-value { color: var(--green); }
.quiz-results-stat.wrong .quiz-results-stat-value { color: var(--red); }
.quiz-results-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* CORRECTION SCREEN */
.quiz-correction {
  max-width: 900px;
  margin: 2rem auto 4rem;
  padding: 0 1.5rem;
}
.quiz-correction-header {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 2rem;
  text-align: center;
}
.quiz-correction-header h2 {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--ink);
  margin-bottom: .5rem;
}
.quiz-correction-header p {
  font-size: .9rem;
  color: var(--ink3);
}
.quiz-correction-item {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 1.5rem;
}
.quiz-correction-item.correct {
  border-left: 4px solid var(--green);
}
.quiz-correction-item.wrong {
  border-left: 4px solid var(--red);
}
.quiz-correction-q-num {
  font-size: .8rem;
  font-weight: 700;
  color: var(--ink3);
  margin-bottom: .75rem;
}
.quiz-correction-q-text {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 1.5rem;
  line-height: 1.7;
}
.quiz-correction-your-answer {
  background: var(--bg);
  padding: 1rem;
  border-radius: var(--radius2);
  margin-bottom: 1rem;
}
.quiz-correction-label {
  font-size: .75rem;
  font-weight: 700;
  color: var(--ink3);
  text-transform: uppercase;
  letter-spacing: .04em;
  margin-bottom: .5rem;
}
.quiz-correction-answer {
  font-size: .9rem;
  font-weight: 600;
  color: var(--ink);
}
.quiz-correction-answer.correct-ans {
  color: var(--green);
}
.quiz-correction-answer.wrong-ans {
  color: var(--red);
}
.quiz-correction-explanation {
  background: var(--blue3);
  border-left: 4px solid var(--blue);
  padding: 1rem;
  border-radius: var(--radius2);
  margin-top: 1rem;
}
.quiz-correction-explanation-title {
  font-size: .8rem;
  font-weight: 700;
  color: var(--blue2);
  margin-bottom: .5rem;
}
.quiz-correction-explanation-text {
  font-size: .875rem;
  color: var(--blue2);
  line-height: 1.6;
}

/* FOOTER */
footer {
  background: var(--ink);
  padding: 2.5rem 2rem;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 1rem;
  margin-top: auto;
}
.footer-logo { font-size: 1.1rem; font-weight: 800; color: #fff; }
.footer-logo span { color: var(--blue); }
footer ul { display:flex; gap:2rem; list-style:none; }
footer ul a { font-size:.82rem; color:rgba(255,255,255,.4); text-decoration:none; transition: color .15s; }
footer ul a:hover { color: rgba(255,255,255,.7); }
.footer-copy { font-size:.75rem; color:rgba(255,255,255,.2); font-family:'JetBrains Mono',monospace; }

/* RESPONSIVE */
@media (max-width: 768px) {
  .nav-badge { display: none; }
  .nav-links { gap: 1rem; }
  .nav-links li:not(:last-child):not(:nth-last-child(2)) { display: none; }
  .quiz-hero { padding: 3rem 1.25rem 2.5rem; }
  .quiz-start-card,
  .quiz-question-card,
  .quiz-results-card {
    padding: 2rem 1.5rem;
  }
  .quiz-results-score {
    font-size: 2.5rem;
  }
  .quiz-results-score span {
    font-size: 1.5rem;
  }
  .quiz-actions {
    flex-direction: column;
  }
  .btn-next {
    margin-left: 0;
    width: 100%;
  }
}

/* ══════════════════════════════════════
   CHAPTER SELECTION SCREEN
   ══════════════════════════════════════ */
.chapter-wrap {
  max-width: 860px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 3rem;
}

.chapter-header {
  text-align: center;
  margin-bottom: 2rem;
}
.chapter-badge {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  background: var(--blue3);
  color: var(--blue2);
  font-size: .72rem;
  font-weight: 700;
  padding: .35rem .875rem;
  border-radius: 20px;
  letter-spacing: .02em;
  margin-bottom: .875rem;
}
.chapter-header h2 {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--ink);
  letter-spacing: -.02em;
  margin-bottom: .5rem;
  line-height: 1.2;
}
.chapter-header p {
  font-size: .9rem;
  color: var(--ink3);
  line-height: 1.6;
}

.chapter-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .875rem;
}

.chapter-card {
  background: var(--white);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1rem;
  display: flex;
  flex-direction: column;
  gap: .5rem;
  cursor: pointer;
  text-align: left;
  font-family: 'Plus Jakarta Sans', sans-serif;
  transition: transform .15s, box-shadow .15s, border-color .15s;
  box-shadow: var(--shadow);
}
.chapter-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 6px 20px rgba(37,99,235,.13);
  border-color: var(--blue4);
}
.chapter-card:active { transform: translateY(0); }

.chapter-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.15rem;
  flex-shrink: 0;
}
.chapter-name {
  font-size: .875rem;
  font-weight: 700;
  color: var(--ink);
  line-height: 1.3;
}
.chapter-desc {
  font-size: .75rem;
  color: var(--ink3);
  line-height: 1.5;
}

/* Carte Mixte — pleine largeur, fond dégradé */
.chapter-card--mixte {
  grid-column: 1 / -1;
  flex-direction: row;
  align-items: center;
  gap: 1rem;
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 100%);
  border-color: transparent;
  padding: 1.25rem 1.5rem;
}
.chapter-card--mixte:hover {
  border-color: transparent;
  box-shadow: 0 8px 28px rgba(37,99,235,.35);
}
.chapter-card--mixte .chapter-name { color: #fff; font-size: 1rem; }
.chapter-card--mixte .chapter-desc { color: rgba(255,255,255,.72); font-size: .82rem; }

/* Responsive */
@media (max-width: 768px) {
  .chapter-grid { grid-template-columns: repeat(2, 1fr); }
  .chapter-card--mixte { flex-direction: column; align-items: flex-start; }
}
@media (max-width: 480px) {
  .chapter-grid { grid-template-columns: 1fr; }
  .chapter-card--mixte { grid-column: 1; }
}