/* ===== VARIABLES CSS ===== */
:root {
  /* Couleurs - Mode clair */
  --primary-color: #3a86ff;
  --secondary-color: #8338ec;
  --accent-color: #ff006e;
  --text-color: #333333;
  --text-light: #6c757d;
  --bg-color: #ffffff;
  --bg-secondary: #f8f9fa;
  --border-color: #e9ecef;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  
  /* Typographie */
  --font-family: 'Inter', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  
  /* Espacements */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Bordures */
  --border-radius: 8px;
  --border-radius-lg: 12px;
  
  /* Transitions */
  --transition: all 0.3s ease;
}

/* Mode sombre */
[data-theme="dark"] {
  --primary-color: #4dabf7;
  --secondary-color: #9775fa;
  --accent-color: #ff6b6b;
  --text-color: #f8f9fa;
  --text-light: #adb5bd;
  --bg-color: #121212;
  --bg-secondary: #1e1e1e;
  --border-color: #343a40;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
}

/* ===== RESET ET BASE ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--bg-color);
  transition: var(--transition);
}

/* ===== TYPOGRAPHIE ===== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--space-md);
}

h1 {
  font-size: var(--font-size-5xl);
}

h2 {
  font-size: var(--font-size-4xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

p {
  margin-bottom: var(--space-md);
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--secondary-color);
}

/* ===== LAYOUT ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

section {
  padding: var(--space-3xl) 0;
}

/* ===== HEADER ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background-color: var(--bg-color);
  box-shadow: var(--shadow);
  z-index: 1000;
  transition: var(--transition);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) 0;
}

.logo {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--text-color);
}

.logo span {
  color: var(--primary-color);
}

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--space-xl);
}

.nav-links a {
  color: var(--text-color);
  font-weight: 500;
  position: relative;
}

.nav-links a:hover {
  color: var(--primary-color);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--primary-color);
  transition: var(--transition);
}

.nav-links a:hover::after {
  width: 100%;
}

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: var(--font-size-lg);
  padding: var(--space-sm);
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.theme-toggle:hover {
  background-color: var(--bg-secondary);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  display: block;
  width: 25px;
  height: 3px;
  background-color: var(--text-color);
  margin: 2px 0;
  transition: var(--transition);
}

/* ===== HERO SECTION ===== */
.hero {
  padding-top: calc(var(--space-3xl) + 80px);
  min-height: 100vh;
  display: flex;
  align-items: center;
  background-color: var(--bg-secondary);
}

.hero .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
  align-items: center;
}

.hero-title {
  font-size: var(--font-size-5xl);
  margin-bottom: var(--space-lg);
}

.highlight {
  color: var(--primary-color);
}

.hero-subtitle {
  font-size: var(--font-size-xl);
  color: var(--text-light);
  margin-bottom: var(--space-2xl);
}

.hero-buttons {
  display: flex;
  gap: var(--space-md);
}

.btn {
  display: inline-block;
  padding: var(--space-md) var(--space-xl);
  border-radius: var(--border-radius);
  font-weight: 500;
  text-align: center;
  transition: var(--transition);
  border: none;
  cursor: pointer;
  font-size: var(--font-size-base);
}

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

.btn-primary:hover {
  background-color: var(--secondary-color);
  color: white;
  transform: translateY(-2px);
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-color);
  border: 2px solid var(--border-color);
}

.btn-secondary:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  transform: translateY(-2px);
}

.hero-visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

/* ===== ANIMATIONS MATHÉMATIQUES INTERACTIVES ===== */
.math-shapes {
  position: relative;
  width: 350px;
  height: 350px;
}

.shape {
  position: absolute;
  border-radius: var(--border-radius-lg);
  transition: var(--transition);
  cursor: pointer;
  overflow: hidden;
  background: var(--bg-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow);
}

.shape:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
  z-index: 10;
}

/* Forme 1 - Graphique de fonction */
.shape-1 {
  width: 160px;
  height: 160px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  top: 20px;
  left: 20px;
  animation: float 6s ease-in-out infinite;
}

.shape-1 .graph {
  width: 100%;
  height: 100%;
  position: relative;
  background: transparent;
}

.shape-1 .graph .function-svg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.shape-1 .graph .function-curve {
  fill: none;
  stroke: white;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 300;
  stroke-dashoffset: 300;
}

.shape-1:hover .graph .function-curve {
  animation: drawCurve 2s ease-in-out forwards;
}

@keyframes drawCurve {
  to { stroke-dashoffset: 0; }
}

.shape-1 .graph::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 0;
  width: 100%;
  height: 2px;
  background: rgba(255, 255, 255, 0.3);
}

.shape-1 .graph::after {
  content: '';
  position: absolute;
  left: 50%;
  top: 0;
  width: 2px;
  height: 100%;
  background: rgba(255, 255, 255, 0.3);
}

.shape-1:hover .graph::before {
  animation: drawXAxis 1.5s ease-in-out;
}

.shape-1:hover .graph::after {
  animation: drawYAxis 1.5s ease-in-out;
}

@keyframes drawXAxis {
  0% { width: 0; opacity: 0; }
  100% { width: 100%; opacity: 1; }
}

@keyframes drawYAxis {
  0% { height: 0; opacity: 0; }
  100% { height: 100%; opacity: 1; }
}

.shape-1 .equation {
  position: absolute;
  bottom: 10px;
  right: 10px;
  color: white;
  font-size: var(--font-size-sm);
  font-weight: 500;
  opacity: 0;
  transform: translateY(10px);
  transition: var(--transition);
}

.shape-1:hover .equation {
  opacity: 1;
  transform: translateY(0);
}

/* Animation de la courbe de fonction */
.shape-1 .graph .function-line {
  position: absolute;
  top: 50%;
  left: 10%;
  width: 80%;
  height: 2px;
  background: white;
  transform-origin: left center;
  opacity: 0;
}

.shape-1:hover .graph .function-line {
  animation: drawFunction 2s ease-in-out forwards;
}

@keyframes drawFunction {
  0% {
    transform: scaleX(0);
    opacity: 0;
  }
  50% {
    transform: scaleX(1);
    opacity: 1;
  }
  100% {
    transform: scaleX(1);
    opacity: 1;
  }
}

/* Forme 2 - Forme géométrique */
.shape-2 {
  width: 120px;
  height: 120px;
  background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
  bottom: 40px;
  left: 60px;
  animation: float 8s ease-in-out infinite 1s;
}

.shape-2 .polygon {
  width: 60px;
  height: 60px;
  background: rgba(255, 255, 255, 0.9);
  clip-path: circle(50% at 50% 50%);
  transition: var(--transition);
}

.shape-2:hover .polygon {
  transform: rotate(180deg) scale(1.2);
  background: rgba(255, 255, 255, 1);
}

.shape-2 .equation {
  position: absolute;
  top: 10px;
  left: 10px;
  color: white;
  font-size: var(--font-size-sm);
  font-weight: 500;
  opacity: 0;
  transform: translateX(-10px);
  transition: var(--transition);
}

.shape-2:hover .equation {
  opacity: 1;
  transform: translateX(0);
}

/* Animation des points du polygone */
.shape-2 .polygon::before {
  content: '';
  position: absolute;
  width: 4px;
  height: 4px;
  background: var(--accent-color);
  border-radius: 50%;
  top: -2px;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
}

.shape-2:hover .polygon::before {
  animation: blink 1s ease-in-out 3;
}

@keyframes blink {
  0%, 100% { opacity: 0; }
  50% { opacity: 1; }
}

/* Forme 3 - Symbole d'intégrale */
.shape-3 {
  width: 100px;
  height: 100px;
  background: linear-gradient(135deg, var(--accent-color), #ff8c00);
  top: 60px;
  right: 40px;
  animation: float 7s ease-in-out infinite 0.5s;
}

.shape-3 .integral {
  position: relative;
  width: 40px;
  height: 60px;
  color: white;
  font-size: var(--font-size-3xl);
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
}

.shape-3 .integral::before {
  content: '∫';
  font-family: 'Times New Roman', serif;
}

.shape-3:hover .integral {
  animation: integrate 2s ease-in-out;
}

@keyframes integrate {
  0% {
    transform: scale(1) translateY(0);
  }
  25% {
    transform: scale(1.2) translateY(-5px);
  }
  50% {
    transform: scale(1.1) translateY(5px);
  }
  75% {
    transform: scale(1.2) translateY(-3px);
  }
  100% {
    transform: scale(1) translateY(0);
  }
}

.shape-3 .equation {
  position: absolute;
  bottom: 8px;
  left: 8px;
  color: white;
  font-size: var(--font-size-xs);
  font-weight: 500;
  opacity: 0;
  transform: scale(0.8);
  transition: var(--transition);
}

.shape-3:hover .equation {
  opacity: 1;
  transform: scale(1);
}

/* Animation des limites d'intégration */
.shape-3 .integral::after {
  content: '';
  position: absolute;
  width: 20px;
  height: 2px;
  background: white;
  bottom: -5px;
  left: 50%;
  transform: translateX(-50%);
  opacity: 0;
}

.shape-3:hover .integral::after {
  animation: drawIntegralLimits 1.5s ease-in-out forwards;
}

@keyframes drawIntegralLimits {
  0% {
    width: 0;
    opacity: 0;
  }
  50% {
    width: 20px;
    opacity: 1;
  }
  100% {
    width: 20px;
    opacity: 1;
  }
}

/* Effets de particules mathématiques au survol */
.shape::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at center, transparent 30%, rgba(255, 255, 255, 0.1) 70%);
  opacity: 0;
  transition: var(--transition);
}

.shape:hover::before {
  opacity: 1;
  animation: ripple 2s ease-in-out infinite;
}

@keyframes ripple {
  0% {
    transform: scale(1);
    opacity: 0.5;
  }
  50% {
    transform: scale(1.1);
    opacity: 0.3;
  }
  100% {
    transform: scale(1);
    opacity: 0.5;
  }
}

/* Indicateur d'interactivité */
.shape::after {
  content: '🔍';
  position: absolute;
  top: 5px;
  right: 5px;
  font-size: var(--font-size-sm);
  opacity: 0;
  transform: scale(0.8);
  transition: var(--transition);
}

.shape:hover::after {
  opacity: 0.7;
  transform: scale(1);
  animation: pulse 1s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); }
}

/* Mode sombre - ajustements */
[data-theme="dark"] .shape {
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
}

[data-theme="dark"] .shape:hover {
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.4);
}

/* Animation de flottement améliorée */
@keyframes float {
  0%, 100% {
    transform: translateY(0) rotate(0deg);
  }
  33% {
    transform: translateY(-10px) rotate(1deg);
  }
  66% {
    transform: translateY(5px) rotate(-1deg);
  }
}

/* ===== ABOUT SECTION ===== */
.about {
  background-color: var(--bg-color);
}

.section-title {
  text-align: center;
  margin-bottom: var(--space-2xl);
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 4px;
  background-color: var(--primary-color);
  margin: var(--space-md) auto;
  border-radius: 2px;
}

.about-content {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--space-2xl);
  align-items: center;
}

/* Troncature À propos à 15 lignes - conteneur */
.about-text {
  line-height: 1.7;
}

.about-text.clamped {
  overflow: hidden;
}

.about-text.expanded {
  overflow: visible;
}

.about-stats {
  display: flex;
  justify-content: space-between;
  margin-top: var(--space-xl);
}

.stat {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--primary-color);
}

.stat-label {
  font-size: var(--font-size-sm);
  color: var(--text-light);
}

.about-image {
  display: flex;
  justify-content: center;
}

.image-placeholder {
  width: 250px;
  height: 250px;
  background-color: var(--bg-secondary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  border: 4px solid var(--border-color);
}

.image-placeholder img.profile-photo {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  display: block;
}

/* ===== SKILLS SECTION - CIRCULAR PROGRESS BARS ===== */
.skills {
  background-color: var(--bg-secondary);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-2xl);
  justify-items: center;
}

.skill-circle {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  max-width: 300px;
  padding: var(--space-lg);
  background: var(--bg-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.skill-circle:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.circular-progress {
  position: relative;
  width: 160px;
  height: 160px;
  margin-bottom: var(--space-md);
}

.circular-progress svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.circular-progress circle {
  fill: transparent;
  stroke-width: 8;
  stroke-linecap: round;
  transform-origin: center;
}

.circular-progress .background {
  stroke: var(--border-color);
}

.circular-progress .progress {
  stroke: var(--primary-color);
  stroke-dasharray: 440;
  stroke-dashoffset: 440;
  transition: stroke-dashoffset 1.5s ease-in-out;
}

.progress-value {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--primary-color);
}

.skill-name {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-color);
  margin: var(--space-sm) 0 var(--space-xs);
}

.skill-description {
  font-size: var(--font-size-sm);
  color: var(--text-light);
  line-height: 1.5;
  margin: 0;
}

/* Animation des cercles au survol */
.skill-circle:hover .circular-progress .progress {
  stroke: var(--secondary-color);
}

.skill-circle:hover .progress-value {
  color: var(--secondary-color);
}

/* Mode sombre */
[data-theme="dark"] .skill-circle {
  background: var(--bg-color);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

[data-theme="dark"] .skill-circle:hover {
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
}

/* Responsive */
@media (max-width: 768px) {
  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-xl);
  }
  
  .circular-progress {
    width: 140px;
    height: 140px;
  }
  
  .skill-name {
    font-size: var(--font-size-base);
  }
  
  .skill-description {
    font-size: var(--font-size-xs);
  }
}

@media (max-width: 480px) {
  .skills-grid {
    grid-template-columns: 1fr;
  }
  
  .circular-progress {
    width: 120px;
    height: 120px;
  }
  
  .progress-value {
    font-size: var(--font-size-lg);
  }
}

/* ===== PROJECTS SECTION ===== */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--space-xl);
}

.project-card {
  background-color: var(--bg-color);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.project-image {
  height: 200px;
  background-color: var(--bg-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  position: relative;
  overflow: hidden;
  cursor: pointer;
}

.project-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: var(--transition);
}

.project-image:hover .project-overlay {
  opacity: 1;
}

.view-icon {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-sm);
}

.view-text {
  color: white;
  font-weight: 500;
}

.project-content {
  padding: var(--space-xl);
}

.project-content p {
  line-height: 1.6;
  margin-bottom: var(--space-xs);
  display: -webkit-box;
  -webkit-line-clamp: 5;
  -webkit-box-orient: vertical;
  line-clamp: 5;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: var(--transition);
}

.project-content p.expanded {
  display: block;
  overflow: visible;
  text-overflow: initial;
}

/* Conteneur pour positionner le lien “Lire plus” en bas à droite
   lorsqu’il est utilisé dans les cartes de projets. */
.description-wrapper {
  position: relative;
}

/* Style générique du lien inline “Lire plus/Lire moins”.
   - Absolu pour les cartes projets (en bas à droite du résumé).
   - Couleur et soulignement pour suggérer l’interactivité.
*/
.read-more-inline {
  position: absolute;
  bottom: 0;
  right: 0;
  background: var(--bg-color);
  padding-left: var(--space-xs);
  color: var(--primary-color);
  font-weight: 500;
  font-size: var(--font-size-sm);
  text-decoration: underline;
  cursor: pointer;
  transition: var(--transition);
}

/* Spécifique À propos:
   - Le lien s’insère dans le flux du 1er paragraphe.
   - Empêcher le retour à la ligne pour garder “… Lire plus” sur une seule ligne. */
.about-text .read-more-inline {
  position: static;
  display: inline;
  background: transparent;
  padding-left: 0;
  margin-left: 0.25rem;
  white-space: nowrap;
}

/* Paragraphes supplémentaires de la section À propos
   masqués par défaut en mode réduit. */
.about-text .hidden-abt {
  display: none;
}

.read-more-inline:hover {
  color: var(--secondary-color);
}

.project-link {
  background: none;
  border: none;
  color: var(--primary-color);
  font-weight: 500;
  cursor: pointer;
  padding: 0;
  margin-top: var(--space-lg);
  font-family: inherit;
  font-size: inherit;
}

.project-link:hover {
  color: var(--secondary-color);
}

/* ===== CONTACT SECTION ===== */
.contact-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-2xl);
}

.contact-info h3 {
  margin-bottom: var(--space-md);
}

.contact-details {
  margin-top: var(--space-xl);
}

.tutor-widget {
  margin-top: var(--space-xl);
}

.contact-item {
  display: flex;
  align-items: center;
  margin-bottom: var(--space-md);
}

.contact-icon {
  margin-right: var(--space-md);
  font-size: var(--font-size-lg);
}

.contact-form {
  background-color: var(--bg-secondary);
  padding: var(--space-xl);
  border-radius: var(--border-radius-lg);
}

.form-group {
  margin-bottom: var(--space-lg);
}

.form-group label {
  display: block;
  margin-bottom: var(--space-sm);
  font-weight: 500;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: var(--space-md);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: var(--font-family);
  transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(58, 134, 255, 0.2);
}

/* ===== FOOTER ===== */
.footer {
  background-color: var(--bg-secondary);
  padding: var(--space-2xl) 0 var(--space-md);
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-xl);
}

.footer-links h4,
.footer-social h4 {
  margin-bottom: var(--space-md);
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--space-sm);
}

.footer-social .social-links {
  display: flex;
  gap: var(--space-md);
}

.footer-bottom {
  text-align: center;
  padding-top: var(--space-md);
  border-top: 1px solid var(--border-color);
  color: var(--text-light);
  font-size: var(--font-size-sm);
}

/* ===== SCROLL TO TOP BUTTON ===== */
.scroll-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 45px;
  height: 45px;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all 0.3s ease-in-out;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  z-index: 1000;
}

.scroll-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.scroll-to-top:hover {
  background-color: var(--secondary-color);
  transform: translateY(-3px);
  box-shadow: 0 6px 15px rgba(0, 0, 0, 0.2);
}

.scroll-to-top:active {
  transform: translateY(-1px);
}

.scroll-to-top svg {
  transition: transform 0.3s ease;
}

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

/* ===== MODAL STYLES ===== */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: var(--space-lg);
}

.modal.open {
  display: flex;
}

.modal-container {
  background: var(--bg-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-lg);
  width: 95vw;
  max-width: 900px;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
}

@media (min-width: 992px) {
  .modal-container {
    min-width: 700px;
    width: min(900px, 80vw);
  }
}

.modal-content {
  padding: var(--space-2xl);
}

.modal-close {
  position: absolute;
  top: var(--space-lg);
  right: var(--space-lg);
  background: none;
  border: none;
  font-size: var(--font-size-xl);
  cursor: pointer;
  color: var(--text-light);
  padding: var(--space-sm);
}

.modal-close:hover {
  color: var(--text-color);
}

.modal-header {
  margin-bottom: var(--space-xl);
  text-align: center;
}

.modal-icon {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-md);
}

.modal-title {
  margin-bottom: var(--space-sm);
}

.modal-category {
  color: var(--text-light);
  font-size: var(--font-size-sm);
}

.modal-body {
  display: grid;
  gap: var(--space-xl);
}

.modal-image-container {
  text-align: center;
}

.modal-image {
  height: 300px;
  background: var(--bg-secondary);
  border-radius: var(--border-radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-light);
  margin-bottom: var(--space-md);
  overflow: hidden;
}

.modal-image img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
  border-radius: var(--border-radius);
}

.modal-description h3,
.modal-details h4 {
  margin-bottom: var(--space-md);
}

.detail-item {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-lg);
}

.detail-icon {
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

.detail-content ul {
  padding-left: var(--space-lg);
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.tech-tags span {
  background: var(--bg-secondary);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--border-radius);
  font-size: var(--font-size-sm);
}

.modal-footer {
  display: flex;
  justify-content: space-between;
  margin-top: var(--space-xl);
  gap: var(--space-md);
}

.modal-btn-close {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-color);
}

.modal-btn-close:hover {
  background: var(--bg-secondary);
}

/* ===== ANIMATIONS ===== */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.8s ease-out, transform 0.8s ease-out;
  will-change: opacity, transform;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Styles pour les notifications de concepts mathématiques */
@keyframes fadeIn {
  from { opacity: 0; transform: translate(-50%, -60%); }
  to { opacity: 1; transform: translate(-50%, -50%); }
}

@keyframes fadeOut {
  from { opacity: 1; transform: translate(-50%, -50%); }
  to { opacity: 0; transform: translate(-50%, -60%); }
}

.math-concept-notification {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--bg-color);
  color: var(--text-color);
  padding: var(--space-lg);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-lg);
  z-index: 10000;
  max-width: 300px;
  text-align: center;
  border-left: 4px solid var(--primary-color);
  animation: fadeIn 0.3s ease-out;
  font-size: var(--font-size-sm);
  line-height: 1.4;
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 992px) {
  .hero .container {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .about-content {
    grid-template-columns: 1fr;
  }
  
  .contact-content {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    grid-template-columns: 1fr 1fr;
  }
  
  .modal-body {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  .nav-links {
    position: fixed;
    top: 70px;
    left: 0;
    width: 100%;
    background-color: var(--bg-color);
    flex-direction: column;
    align-items: center;
    padding: var(--space-xl);
    box-shadow: var(--shadow);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
  }
  
  .nav-links.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .hero-title {
    font-size: var(--font-size-4xl);
  }
  
  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }
  
  .about-stats {
    flex-direction: column;
    gap: var(--space-lg);
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .footer-social .social-links {
    justify-content: center;
  }
  
  .modal-footer {
    flex-direction: column;
  }
  
  .scroll-to-top {
    bottom: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
  }
}

/* Responsive design pour les animations mathématiques */
@media (max-width: 768px) {
  .math-shapes {
    width: 280px;
    height: 280px;
  }
  
  .shape-1 {
    width: 130px;
    height: 130px;
  }
  
  .shape-2 {
    width: 100px;
    height: 100px;
  }
  
  .shape-3 {
    width: 80px;
    height: 80px;
  }
  
  .shape .equation {
    font-size: var(--font-size-xs);
  }
}

@media (max-width: 576px) {
  .container {
    padding: 0 var(--space-md);
  }
  
  section {
    padding: var(--space-2xl) 0;
  }
  
  .hero-title {
    font-size: var(--font-size-3xl);
  }
  
  .hero-subtitle {
    font-size: var(--font-size-lg);
  }
  
  .skills-grid,
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  .math-shapes {
    width: 220px;
    height: 220px;
  }
  
  .shape-1 {
    width: 100px;
    height: 100px;
    top: 10px;
    left: 10px;
  }
  
  .shape-2 {
    width: 80px;
    height: 80px;
    bottom: 20px;
    left: 40px;
  }
  
  .shape-3 {
    width: 70px;
    height: 70px;
    top: 40px;
    right: 20px;
  }
  
  .shape .equation {
    display: none; /* Masquer les équations sur très petits écrans */
  }
}

/* Transition pour les interactions tactiles */
@media (hover: none) {
  .shape:hover {
    transform: none;
  }
  
  .shape:active {
    transform: scale(1.05);
  }
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .fade-in {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus styles pour l'accessibilité */
button:focus,
a:focus,
input:focus,
textarea:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}