/* ==========================================================================
   🧠 L'ENGRAMME & LA MICROGLIE — DESIGN SYSTEM
   Thème : Bioluminescence Cérébrale & Neuro-Immuno-Architecture
   ========================================================================== */

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

:root {
  --bg-deep: #050811;
  --bg-surface: #0a0f1d;
  --bg-surface-elevated: #11182c;
  --bg-card: rgba(15, 23, 42, 0.75);
  --bg-card-hover: rgba(22, 34, 64, 0.85);

  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-bright: rgba(255, 255, 255, 0.16);

  /* Couleurs sémantiques Neurosciences */
  --engram-gold: #f59e0b;
  --engram-glow: rgba(245, 158, 11, 0.35);
  --microglia-emerald: #10b981;
  --microglia-glow: rgba(16, 185, 129, 0.35);
  --synapse-blue: #38bdf8;
  --synapse-glow: rgba(56, 189, 248, 0.35);
  --neural-purple: #a855f7;
  --pruning-coral: #f43f5e;

  /* Typographie & Contraste */
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-dim: #64748b;

  --font-heading: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Rayons et ombres */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-pill: 9999px;

  --shadow-subtle: 0 4px 20px rgba(0, 0, 0, 0.3);
  --shadow-glow-blue: 0 0 30px rgba(56, 189, 248, 0.18);
  --shadow-glow-gold: 0 0 30px rgba(245, 158, 11, 0.2);
  --shadow-glow-emerald: 0 0 30px rgba(16, 185, 129, 0.2);

  --transition-fast: 0.18s ease;
  --transition-normal: 0.28s cubic-bezier(0.16, 1, 0.3, 1);
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  color-scheme: dark;
  font-size: 16px;
}

body {
  background-color: var(--bg-deep);
  color: var(--text-main);
  font-family: var(--font-body);
  line-height: 1.7;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 15% 15%, rgba(56, 189, 248, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 85% 30%, rgba(168, 85, 247, 0.07) 0%, transparent 45%),
    radial-gradient(circle at 50% 70%, rgba(16, 185, 129, 0.06) 0%, transparent 50%),
    radial-gradient(circle at 20% 90%, rgba(245, 158, 11, 0.06) 0%, transparent 45%);
  background-attachment: fixed;
}

/* ==========================================================================
   Barre de Progression de Lecture (Scroll Progress)
   ========================================================================== */
#progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3.5px;
  background: linear-gradient(90deg, var(--synapse-blue), var(--engram-gold), var(--microglia-emerald));
  z-index: 9999;
  transform-origin: 0 50%;
  transform: scaleX(0);
}

@media (prefers-reduced-motion: no-preference) {
  @supports (animation-timeline: scroll()) {
    @keyframes grow-progress {
      from { transform: scaleX(0); }
      to { transform: scaleX(1); }
    }

    #progress {
      animation: grow-progress auto linear;
      animation-timeline: scroll();
    }
  }
}

/* ==========================================================================
   En-tête & Barre de Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(5, 8, 17, 0.8);
  border-bottom: 1px solid var(--border-subtle);
  transition: all var(--transition-normal);
}

.header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand-badge {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.brand-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.2), rgba(245, 158, 11, 0.2));
  border: 1px solid rgba(56, 189, 248, 0.4);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.2);
}

.brand-title {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
  background: linear-gradient(90deg, #fff, #94a3b8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.brand-subtitle {
  font-size: 0.72rem;
  color: var(--synapse-blue);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-pill);
  transition: all var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: #fff;
  background: rgba(255, 255, 255, 0.06);
}

.btn-interactive-jump {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  font-size: 0.82rem;
  font-weight: 600;
  border-radius: var(--radius-pill);
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.2), rgba(16, 185, 129, 0.2));
  border: 1px solid rgba(245, 158, 11, 0.4);
  color: #fbbf24;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.btn-interactive-jump:hover {
  background: linear-gradient(135deg, rgba(245, 158, 11, 0.35), rgba(16, 185, 129, 0.35));
  box-shadow: 0 0 16px rgba(245, 158, 11, 0.25);
  transform: translateY(-1px);
}

/* ==========================================================================
   Hero Banner / Couverture Didactique
   ========================================================================== */
.hero-section {
  position: relative;
  padding: 80px 24px 60px;
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
}

.hero-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(56, 189, 248, 0.1);
  border: 1px solid rgba(56, 189, 248, 0.3);
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--synapse-blue);
  margin-bottom: 24px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: clamp(2.4rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
  color: #fff;
}

.hero-title .gradient-engram {
  background: linear-gradient(135deg, #fbbf24, #f59e0b, #ea580c);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-title .gradient-microglia {
  background: linear-gradient(135deg, #34d399, #10b981, #059669);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-lead {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--text-muted);
  max-width: 820px;
  margin: 0 auto 36px;
  font-weight: 400;
  line-height: 1.65;
}

.hero-lead strong {
  color: #f1f5f9;
}

.hero-duality-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
  text-align: left;
}

.duality-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  backdrop-filter: blur(12px);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.duality-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
}

.duality-card.engram::before {
  background: linear-gradient(90deg, var(--engram-gold), transparent);
}

.duality-card.microglia::before {
  background: linear-gradient(90deg, var(--microglia-emerald), transparent);
}

.duality-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-bright);
}

.duality-card.engram:hover {
  box-shadow: var(--shadow-glow-gold);
}

.duality-card.microglia:hover {
  box-shadow: var(--shadow-glow-emerald);
}

.duality-badge {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 3px 8px;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 12px;
}

.duality-card.engram .duality-badge {
  background: rgba(245, 158, 11, 0.15);
  color: #fbbf24;
}

.duality-card.microglia .duality-badge {
  background: rgba(16, 185, 129, 0.15);
  color: #34d399;
}

.duality-card h3 {
  font-family: var(--font-heading);
  font-size: 1.25rem;
  color: #fff;
  margin-bottom: 8px;
}

.duality-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ==========================================================================
   Conteneur Principal avec Sommaire Flottant
   ========================================================================== */
.main-layout {
  max-width: 1280px;
  margin: 0 auto;
  padding: 40px 24px 100px;
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 48px;
  align-items: start;
}

@media (max-width: 960px) {
  .main-layout {
    grid-template-columns: 1fr;
    gap: 32px;
  }
}

/* Sommaire Flottant */
.sticky-sidebar {
  position: sticky;
  top: 80px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px;
  backdrop-filter: blur(12px);
}

@media (max-width: 960px) {
  .sticky-sidebar {
    position: relative;
    top: 0;
  }
}

.sidebar-title {
  font-family: var(--font-heading);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-dim);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.toc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.toc-link {
  display: block;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: 6px;
  transition: all var(--transition-fast);
  border-left: 2px solid transparent;
}

.toc-link:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.04);
}

.toc-link.active {
  color: var(--synapse-blue);
  background: rgba(56, 189, 248, 0.08);
  border-left-color: var(--synapse-blue);
  font-weight: 600;
}

/* ==========================================================================
   Sections de Contenu Didactique
   ========================================================================== */
.content-body {
  min-width: 0;
}

.article-section {
  margin-bottom: 72px;
  scroll-margin-top: 90px;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.76rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--synapse-blue);
  background: rgba(56, 189, 248, 0.1);
  padding: 3px 10px;
  border-radius: var(--radius-pill);
  margin-bottom: 12px;
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.7rem, 3vw, 2.3rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  color: #fff;
  margin-bottom: 20px;
  line-height: 1.25;
}

.section-lead {
  font-size: 1.05rem;
  color: #cbd5e1;
  margin-bottom: 28px;
  line-height: 1.7;
}

.prose {
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.75;
}

.prose p {
  margin-bottom: 20px;
}

.prose strong {
  color: #fff;
  font-weight: 600;
}

/* Callout pédagogique */
.pedagogy-callout {
  background: rgba(15, 23, 42, 0.85);
  border-left: 4px solid var(--synapse-blue);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 20px 24px;
  margin: 32px 0;
  border-top: 1px solid var(--border-subtle);
  border-right: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.pedagogy-callout.callout-engram {
  border-left-color: var(--engram-gold);
}

.pedagogy-callout.callout-microglia {
  border-left-color: var(--microglia-emerald);
}

.callout-header {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 8px;
  color: #fff;
}

.callout-body {
  font-size: 0.92rem;
  color: #cbd5e1;
  line-height: 1.65;
}

/* Grille de cartes conceptuelles */
.concept-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
  margin: 28px 0;
}

.concept-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 22px;
  transition: all var(--transition-fast);
}

.concept-card:hover {
  background: var(--bg-surface-elevated);
  border-color: var(--border-bright);
  transform: translateY(-2px);
}

.concept-icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.concept-card h4 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  color: #fff;
  margin-bottom: 8px;
}

.concept-card p {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* Frise chronologique */
.timeline {
  position: relative;
  padding-left: 28px;
  margin: 36px 0;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 6px;
  top: 8px;
  bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--synapse-blue), var(--engram-gold), var(--microglia-emerald));
}

.timeline-item {
  position: relative;
  margin-bottom: 28px;
}

.timeline-dot {
  position: absolute;
  left: -28px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--bg-deep);
  border: 2px solid var(--synapse-blue);
  box-shadow: 0 0 8px var(--synapse-blue);
}

.timeline-item:nth-child(2) .timeline-dot {
  border-color: var(--engram-gold);
  box-shadow: 0 0 8px var(--engram-gold);
}

.timeline-item:nth-child(3) .timeline-dot {
  border-color: var(--microglia-emerald);
  box-shadow: 0 0 8px var(--microglia-emerald);
}

.timeline-year {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--synapse-blue);
  margin-bottom: 4px;
}

.timeline-title {
  font-family: var(--font-heading);
  font-size: 1rem;
  color: #fff;
  font-weight: 700;
  margin-bottom: 4px;
}

.timeline-desc {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* ==========================================================================
   Visualiseur & Simulateur Interactif (Canvas Neuro-Immuno)
   ========================================================================== */
.simulator-container {
  background: #020617;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-subtle), var(--shadow-glow-blue);
  margin: 40px 0;
}

.simulator-header {
  padding: 16px 24px;
  background: rgba(15, 23, 42, 0.9);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.simulator-title-group {
  display: flex;
  align-items: center;
  gap: 10px;
}

.simulator-status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #34d399;
  padding: 3px 10px;
  border-radius: var(--radius-pill);
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #10b981;
  animation: pulse-dot 1.5s infinite;
}

@keyframes pulse-dot {
  0% { opacity: 0.4; transform: scale(0.9); }
  50% { opacity: 1; transform: scale(1.2); }
  100% { opacity: 0.4; transform: scale(0.9); }
}

.canvas-wrapper {
  position: relative;
  width: 100%;
  height: 420px;
  background: radial-gradient(circle at center, #0a1128 0%, #030712 100%);
  cursor: crosshair;
}

#neuro-canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.canvas-overlay-legend {
  position: absolute;
  top: 14px;
  left: 14px;
  background: rgba(3, 7, 18, 0.8);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  font-size: 0.75rem;
  backdrop-filter: blur(8px);
  display: flex;
  flex-direction: column;
  gap: 6px;
  pointer-events: none;
}

.legend-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.simulator-controls {
  padding: 16px 24px;
  background: rgba(15, 23, 42, 0.85);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.control-btn-group {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.sim-btn {
  padding: 8px 16px;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: var(--radius-pill);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: all var(--transition-fast);
  border: 1px solid transparent;
}

.sim-btn-engram {
  background: rgba(245, 158, 11, 0.2);
  border-color: rgba(245, 158, 11, 0.5);
  color: #fbbf24;
}

.sim-btn-engram:hover {
  background: rgba(245, 158, 11, 0.35);
  box-shadow: 0 0 15px rgba(245, 158, 11, 0.3);
}

.sim-btn-reactivate {
  background: rgba(56, 189, 248, 0.2);
  border-color: rgba(56, 189, 248, 0.5);
  color: #38bdf8;
}

.sim-btn-reactivate:hover {
  background: rgba(56, 189, 248, 0.35);
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.3);
}

.sim-btn-pruning {
  background: rgba(16, 185, 129, 0.2);
  border-color: rgba(16, 185, 129, 0.5);
  color: #34d399;
}

.sim-btn-pruning:hover {
  background: rgba(16, 185, 129, 0.35);
  box-shadow: 0 0 15px rgba(16, 185, 129, 0.3);
}

.sim-btn-reset {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--border-subtle);
  color: var(--text-muted);
}

.sim-btn-reset:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

.simulator-log {
  padding: 10px 24px;
  background: #060a17;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--synapse-blue);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ==========================================================================
   Quiz Didactique d'Auto-Évaluation
   ========================================================================== */
.quiz-section {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 36px;
  margin: 48px 0;
  backdrop-filter: blur(12px);
}

.quiz-header {
  text-align: center;
  margin-bottom: 32px;
}

.quiz-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 24px;
  margin-bottom: 24px;
}

.question-num {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: var(--engram-gold);
  text-transform: uppercase;
  font-weight: 700;
  margin-bottom: 6px;
}

.question-text {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  color: #fff;
  margin-bottom: 16px;
}

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

.option-btn {
  text-align: left;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  font-size: 0.92rem;
  color: #e2e8f0;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.option-btn:hover:not(:disabled) {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--synapse-blue);
  transform: translateX(4px);
}

.option-btn.correct {
  background: rgba(16, 185, 129, 0.2) !important;
  border-color: #10b981 !important;
  color: #34d399 !important;
  font-weight: 600;
}

.option-btn.wrong {
  background: rgba(244, 63, 94, 0.2) !important;
  border-color: #f43f5e !important;
  color: #fda4af !important;
}

.didactic-feedback {
  margin-top: 14px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  line-height: 1.55;
  display: none;
}

.didactic-feedback.show {
  display: block;
  animation: fadeIn 0.3s ease;
}

.didactic-feedback.success {
  background: rgba(16, 185, 129, 0.12);
  border-left: 3px solid #10b981;
  color: #a7f3d0;
}

.didactic-feedback.error {
  background: rgba(244, 63, 94, 0.12);
  border-left: 3px solid #f43f5e;
  color: #fecdd3;
}

/* ==========================================================================
   Cartes Mémos & Synthèse Finale
   ========================================================================== */
.flashcards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin: 32px 0;
}

.flashcard {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 20px;
  border-top: 3px solid var(--synapse-blue);
  transition: all var(--transition-fast);
}

.flashcard:hover {
  transform: translateY(-3px);
  border-color: var(--border-bright);
}

.flashcard-term {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1rem;
  color: #fff;
  margin-bottom: 6px;
}

.flashcard-def {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.55;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  background: rgba(5, 8, 17, 0.95);
  padding: 40px 24px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
}

.footer-inner {
  max-width: 800px;
  margin: 0 auto;
}

.footer-inner a {
  color: var(--synapse-blue);
  text-decoration: none;
}

.footer-inner a:hover {
  text-decoration: underline;
}

.footer-author-link {
  color: var(--synapse-blue);
  font-weight: 600;
  transition: all var(--transition-fast);
}

.footer-author-link:hover {
  color: #fbbf24 !important;
}

/* Flèche Flottante / Bouton Retour en Haut */
.btn-scroll-top {
  position: fixed;
  bottom: 28px;
  right: 28px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, #0284c7 0%, #0284c7 35%, #d97706 100%);
  color: #ffffff;
  border: 2.5px solid #ffffff;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.85), 0 0 25px rgba(56, 189, 248, 0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 9999999;
  opacity: 0.95;
  pointer-events: auto;
  transform: translateY(0);
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  animation: floatArrow 3s ease-in-out infinite;
}

.btn-scroll-top svg {
  display: block;
  stroke: #ffffff;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.8));
  transition: transform 0.2s ease;
}

.btn-scroll-top:hover svg {
  transform: translateY(-2px);
}

.btn-scroll-top.scrolled {
  opacity: 1;
  box-shadow: 0 10px 32px rgba(0, 0, 0, 0.9), 0 0 30px rgba(245, 158, 11, 0.85);
}

.btn-scroll-top:hover {
  opacity: 1 !important;
  background: linear-gradient(135deg, #38bdf8 0%, #f59e0b 100%);
  border-color: #ffffff;
  box-shadow: 0 12px 35px rgba(245, 158, 11, 0.8), 0 0 35px rgba(56, 189, 248, 0.9);
  transform: translateY(-4px) scale(1.1);
  animation-play-state: paused;
}

@keyframes floatArrow {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-6px);
  }
}

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