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

:root {
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --bg: #0D0D14;
  --bg-card: #13131F;
  --bg-card-hover: #1A1A2A;
  --bg-surface: #1E1E30;
  --border: rgba(255,255,255,0.08);
  --border-hover: rgba(255,255,255,0.15);

  --text-primary: #F0F0F8;
  --text-secondary: #8888AA;
  --text-muted: #55556A;

  --module-algebre: #4F46E5;
  --module-algebre-glow: rgba(79,70,229,0.25);
  --module-algebre-soft: rgba(79,70,229,0.12);

  --module-acp: #0891B2;
  --module-acp-glow: rgba(8,145,178,0.25);
  --module-acp-soft: rgba(8,145,178,0.12);

  --module-nonlin: #7C3AED;
  --module-nonlin-glow: rgba(124,58,237,0.25);
  --module-nonlin-soft: rgba(124,58,237,0.12);

  --module-ica: #059669;
  --module-ica-glow: rgba(5,150,105,0.25);
  --module-ica-soft: rgba(5,150,105,0.12);

  --module-anova: #D97706;
  --module-anova-glow: rgba(217,119,6,0.25);
  --module-anova-soft: rgba(217,119,6,0.12);

  --module-afc: #DB2777;
  --module-afc-glow: rgba(219,39,119,0.25);
  --module-afc-soft: rgba(219,39,119,0.12);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  font-size: 16px;
  min-height: 100vh;
}

a { color: inherit; text-decoration: none; }

h1 { font-size: 2.5rem; font-weight: 700; line-height: 1.2; }
h2 { font-size: 1.75rem; font-weight: 600; line-height: 1.3; }
h3 { font-size: 1.25rem; font-weight: 600; line-height: 1.4; }
h4 { font-size: 1rem; font-weight: 600; }
p { color: var(--text-secondary); line-height: 1.7; }

code, .mono {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--bg-surface);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--text-primary);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.container-narrow {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* NAV */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13,13,20,0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}
.nav-logo {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}
.nav-logo span { /* color set per module in inline styles */ }
.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}
.nav-links a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--text-primary); }

/* CARDS */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: border-color 0.2s, background 0.2s;
}
.card:hover {
  border-color: var(--border-hover);
  background: var(--bg-card-hover);
}

/* MODULE COLOR CLASSES */
.mod-algebre  { --mod-color: var(--module-algebre);  --mod-glow: var(--module-algebre-glow);  --mod-soft: var(--module-algebre-soft); }
.mod-acp      { --mod-color: var(--module-acp);      --mod-glow: var(--module-acp-glow);      --mod-soft: var(--module-acp-soft); }
.mod-nonlin   { --mod-color: var(--module-nonlin);   --mod-glow: var(--module-nonlin-glow);   --mod-soft: var(--module-nonlin-soft); }
.mod-ica      { --mod-color: var(--module-ica);      --mod-glow: var(--module-ica-glow);      --mod-soft: var(--module-ica-soft); }
.mod-anova    { --mod-color: var(--module-anova);    --mod-glow: var(--module-anova-glow);    --mod-soft: var(--module-anova-soft); }
.mod-afc      { --mod-color: var(--module-afc);      --mod-glow: var(--module-afc-glow);      --mod-soft: var(--module-afc-soft); }

.module-card {
  border-color: var(--mod-color, var(--border));
  border-width: 1px;
  position: relative;
  overflow: hidden;
  cursor: pointer;
}
.module-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--mod-color);
}
.module-card:hover {
  box-shadow: 0 0 32px var(--mod-glow, transparent);
  border-color: var(--mod-color);
}

.module-icon {
  width: 44px; height: 44px;
  border-radius: var(--radius-sm);
  background: var(--mod-soft);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 1rem;
  color: var(--mod-color);
}

.module-tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 8px;
  border-radius: 4px;
  background: var(--mod-soft);
  color: var(--mod-color);
  margin-bottom: 0.5rem;
}

/* BADGE */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.75rem;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid;
}
.badge-outline {
  background: transparent;
  border-color: var(--border-hover);
  color: var(--text-secondary);
}

/* PROGRESS BAR */
.progress-bar {
  height: 4px;
  background: var(--bg-surface);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 1rem;
}
.progress-fill {
  height: 100%;
  background: var(--mod-color);
  border-radius: 999px;
  transition: width 0.5s ease;
}

/* SECTION */
.section { padding: 5rem 0; }
.section-sm { padding: 3rem 0; }

.section-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}
.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}
.section-subtitle {
  color: var(--text-secondary);
  font-size: 1rem;
  max-width: 500px;
}

/* GRID */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }

/* PAGE CONTENT LAYOUT */
.page-header {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 3rem;
}
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--text-primary); }
.breadcrumb-sep { color: var(--text-muted); }

/* CONCEPT BLOCK */
.concept-step {
  padding: 1.5rem;
  border-radius: var(--radius-md);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--mod-color, var(--border));
  margin-bottom: 1rem;
}
.concept-step-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--mod-color, var(--text-muted));
  margin-bottom: 0.5rem;
}

/* FORMULE BOX */
.formula-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-hover);
  border-radius: var(--radius-md);
  padding: 1.5rem 2rem;
  margin: 1.5rem 0;
  text-align: center;
  font-size: 1.1rem;
}
.formula-legend {
  font-size: 0.82rem;
  color: var(--text-secondary);
  margin-top: 0.75rem;
  text-align: left;
}
.formula-legend span { color: var(--text-primary); font-family: var(--font-mono); }

/* À RETENIR */
.retenir-box {
  border-radius: var(--radius-md);
  border: 1px solid var(--mod-color, var(--border));
  background: var(--mod-soft, var(--bg-card));
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
}
.retenir-box h4 {
  color: var(--mod-color, var(--text-primary));
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.retenir-box ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.retenir-box li {
  font-size: 0.9rem;
  color: var(--text-secondary);
  padding-left: 1rem;
  position: relative;
}
.retenir-box li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--mod-color, var(--text-muted));
}

/* QUIZ */
.quiz-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 2rem 0;
}
.quiz-box h4 {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 1rem;
}
.quiz-question {
  font-size: 0.95rem;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
  font-weight: 500;
}
.quiz-options { display: flex; flex-direction: column; gap: 0.5rem; }
.quiz-option {
  padding: 0.6rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-surface);
  color: var(--text-secondary);
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.15s;
  text-align: left;
}
.quiz-option:hover { border-color: var(--border-hover); color: var(--text-primary); }
.quiz-option.correct { border-color: var(--module-ica); background: var(--module-ica-soft); color: #6EE7B7; }
.quiz-option.wrong { border-color: var(--module-afc); background: var(--module-afc-soft); color: #FDA4AF; }
.quiz-feedback {
  margin-top: 0.75rem;
  font-size: 0.85rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  display: none;
}
.quiz-feedback.show { display: block; }
.quiz-feedback.correct { background: rgba(5,150,105,0.1); color: #6EE7B7; border: 1px solid rgba(5,150,105,0.3); }
.quiz-feedback.wrong { background: rgba(219,39,119,0.1); color: #FDA4AF; border: 1px solid rgba(219,39,119,0.3); }

/* VIZ CONTAINER */
.viz-container {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin: 2rem 0;
  min-height: 300px;
}
.viz-title {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

/* SIDEBAR LAYOUT */
.content-with-sidebar {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 3rem;
  align-items: start;
}
.sidebar {
  position: sticky;
  top: 80px;
}
.sidebar-nav { list-style: none; }
.sidebar-nav li a {
  display: block;
  padding: 0.4rem 0.75rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
  border-left: 2px solid transparent;
  transition: all 0.15s;
  border-radius: 0 4px 4px 0;
}
.sidebar-nav li a:hover { color: var(--text-primary); border-left-color: var(--border-hover); }
.sidebar-nav li a.active { color: var(--mod-color, var(--text-primary)); border-left-color: var(--mod-color, var(--border)); background: var(--mod-soft, transparent); }

/* FOOTER */
.footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* UTILS */
.text-muted { color: var(--text-muted); }
.text-secondary { color: var(--text-secondary); }
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

/* HAMBURGER MENU */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
  z-index: 200;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s;
}
.nav-toggle.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* MOBILE NAV OVERLAY */
.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 150;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
}
.mobile-nav.open { display: flex; }
.mobile-nav a {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: color 0.2s;
}
.mobile-nav a:hover,
.mobile-nav a.active { color: var(--text-primary); }
.mobile-nav-close {
  position: absolute;
  top: 1.25rem;
  right: 1.5rem;
  font-size: 1.5rem;
  background: none;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav-links { display: none !important; }

  h1 { font-size: 1.6rem; }
  h2 { font-size: 1.3rem; }

  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .content-with-sidebar { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .container, .container-narrow { padding: 0 1rem; }

  .stats-strip { gap: 1rem; flex-wrap: wrap; }
  .stat-number { font-size: 1.2rem; }

  .hero h1 { font-size: 2rem; }
  .hero-actions { flex-direction: column; align-items: flex-start; }

  .exam-strip { flex-direction: column; }
  .method-grid { grid-template-columns: repeat(2, 1fr); }

  /* Tables on mobile */
  table { display: block; overflow-x: auto; white-space: nowrap; }
}

@media (max-width: 480px) {
  .method-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 1.6rem; }
}