/* =====================
   RESET & VARIABLES
===================== */
:root {
  --bg-main: #ffffff;
  --bg-dark: #0a192f;
  --bg-dark-2: #112240;
  --accent: #64ffda;

  --text-main: #4e77a1;
  --text-light: #b8c1ec;

  --radius: 10px;
  --shadow-soft: 0 10px 30px rgba(0,0,0,0.08);
  --shadow-hover: 0 15px 40px rgba(0,0,0,0.12);
}


* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", Arial, sans-serif;
  background: var(--bg-main);
  color: var(--text-main);
  line-height: 1.7;
}

/* =====================
   HEADER & NAV
===================== */
header {
  background: linear-gradient(135deg, var(--bg-dark), var(--bg-dark-2));
  padding: 18px 40px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.25);
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1100px;
  margin: auto;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 24px;
  padding: 0;
  margin: 0;
}

nav a {
  color: var(--text-light);
  text-decoration: none;
  font-weight: 500;
  position: relative;
  transition: color 0.3s ease;
}

nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: width 0.3s ease;
}

nav a:hover {
  color: #fff;
}

nav a:hover::after,
nav a.active::after {
  width: 100%;
}

/* =====================
   HERO
===================== */
.hero {
  text-align: center;
  padding: 120px 20px;
  background: linear-gradient(135deg, var(--bg-dark-2), #020c1b);
  color: #fff;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: 20px;
}

.hero p {
  max-width: 600px;
  margin: auto;
  color: var(--text-light);
}

/* =====================
   BUTTON
===================== */
.btn {
  display: inline-block;
  margin-top: 30px;
  background: var(--accent);
  color: var(--bg-dark);
  padding: 14px 30px;
  border-radius: var(--radius);
  font-weight: bold;
  text-decoration: none;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.btn:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
}

/* =====================
   CONTENT
===================== */
.content {
  padding: 80px 20px;
  max-width: 1100px;
  margin: auto;
}

/* =====================
   GRID & CARDS
===================== */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 30px;
}

.card {
  background: #f8fafc;
  padding: 30px;
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

/* =====================
   FORMS
===================== */
form {
  max-width: 600px;
  margin: auto;
}

input,
textarea {
  width: 100%;
  padding: 14px;
  margin-bottom: 16px;
  border-radius: var(--radius);
  border: 1px solid #ddd;
  font-size: 1rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input:focus,
textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(100,255,218,0.25);
}

button {
  background: var(--accent);
  color: var(--bg-dark);
  padding: 14px;
  border: none;
  border-radius: var(--radius);
  font-weight: bold;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-soft);
}

/* =====================
   FOOTER
===================== */
footer {
  text-align: center;
  padding: 30px 20px;
  background: var(--bg-dark);
  color: var(--text-light);
  margin-top: 80px;
}

/* =====================
   RESPONSIVE
===================== */
@media (max-width: 768px) {

  header {
    padding: 16px 20px;
  }

  nav {
    flex-direction: column;
    gap: 14px;
  }

  nav ul {
    flex-direction: column;
    align-items: center;
    gap: 12px;
  }

  .hero {
    padding: 80px 15px;
  }

  .content {
    padding: 60px 15px;
  }

  .grid {
    grid-template-columns: 1fr;
  }
}
#logo {

  width: 40px;
  height: auto;
}
@media (prefers-color-scheme: dark) {
   :root {
    --bg-main: #0b1220;
    --bg-dark: #020c1b;
    --bg-dark-2: #020c1b;
    --accent: #64ffda;

    --text-main: #e5e7eb;
    --text-light: #9ca3af;

    --shadow-soft: 0 10px 30px rgba(0,0,0,0.5);
    --shadow-hover: 0 15px 40px rgba(0,0,0,0.7);
   }
   body {
    background: var(--bg-main)
   }
   .card {
    background: #111827;
   }
  input,
  textarea {
  background: #020617;
  color: var(--text-main);
  border: 1px solid #1f2937;
  }

  footer {
    background: #020617;
  }
}
/* Ajustement de l'espacement des lettres pour les titres */
h1, h2, h3 {
  letter-spacing: -0.02em;
}
/* Animation pour faire apparaître les cartes au défilement */
.card {
  background: linear-gradient(180deg, #1a3e60, #0f3375);
  border-radius: 16px;
  padding: 32px;
  box-shadow: 0 20px 40px rgba(0,0,0,0.4);
  h2, h3 {
    color: #ffffff;
  }

  /* visible par défaut */
  opacity: 1;
  transform: none;

  transition: opacity 0.6s ease, transform 0.6s ease;
}

.js .card {
  opacity: 0;
  transform: translateY(40px);
}

.js .card.visible {
  opacity: 1;
  transform: translateY(0);
}

.content {
  max-width: 900px;
  margin: 0 auto;
}

.grid {
  display: flex;
  flex-direction: column;
  gap: 40px;
}
/* Styles pour le footer avec icônes sociales */
.footer-content {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer-socials {
  display: flex;
  gap: 16px;
}

.footer-socials a {
  display: inline-flex;
  opacity: 0.7;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.footer-socials a:hover {
  opacity: 1;
  transform: translateY(-2px);
}

.footer-socials img {
  width: 20px;
  height: 20px;
  filter: invert(85%);
}


nav .nav-etudes {
  position: relative;
}

nav .nav-etudes-row {
  display: flex;
  align-items: center;
  gap: 5px;
}

nav .nav-etudes-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 27px;
  height: 29px;
  padding: 0;
  background: transparent;
  color: var(--text-light);
  border: 0;
  border-radius: 5px;
  font: inherit;
  line-height: 1;
  box-shadow: none;
  transform: none;
  transition: color .2s ease, background .2s ease;
}

nav .nav-etudes-toggle:hover,
nav .nav-etudes-toggle:focus-visible {
  background: rgba(100, 255, 218, .12);
  color: var(--accent);
  box-shadow: none;
  transform: none;
}

nav .nav-etudes-toggle span {
  display: inline-block;
  font-size: 1.3rem;
  transition: transform .2s ease;
}

nav .nav-etudes.is-open .nav-etudes-toggle span {
  transform: rotate(180deg);
}

/* nav ul est horizontal dans le CSS existant :
   cette règle force seulement le sous-menu à être vertical. */
nav .nav-etudes-menu {
  display: none;
  position: absolute;
  top: calc(100% + 12px);
  left: -12px;
  z-index: 20;
  min-width: 155px;
  padding: 8px;
  margin: 0;
  flex-direction: column;
  align-items: stretch;
  gap: 3px;
  background: var(--bg-dark-2);
  border: 1px solid rgba(100, 255, 218, .2);
  border-radius: var(--radius);
  box-shadow: 0 12px 28px rgba(0, 0, 0, .25);
}

nav .nav-etudes.is-open .nav-etudes-menu {
  display: flex;
}

nav .nav-etudes-menu a {
  display: block;
  padding: 8px 12px;
  border-radius: 6px;
  white-space: nowrap;
}

nav .nav-etudes-menu a::after {
  display: none;
}

nav .nav-etudes-menu a:hover,
nav .nav-etudes-menu a.active,
nav .nav-etudes-menu a:focus-visible {
  background: rgba(100, 255, 218, .12);
  color: var(--accent);
}

/* Cartes de présentation des études, distinctes des .card animées */
.etudes-intro {
  max-width: 720px;
  margin-bottom: 32px;
}

.etudes-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-top: 28px;
}

.etudes-card {
  display: flex;
  flex-direction: column;
  padding: 28px;
  border-radius: var(--radius);
  background: linear-gradient(145deg, #163e65, #0b2545);
  color: #fff;
  box-shadow: var(--shadow-soft);
  transition: transform .25s ease, box-shadow .25s ease;
}

.etudes-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.etudes-card h3 {
  margin: 0 0 10px;
  color: #fff;
}

.etudes-card p {
  flex-grow: 1;
  color: #d5e1ee;
}

.etudes-card .btn {
  align-self: flex-start;
  margin-top: 14px;
}

.etudes-label {
  color: var(--accent);
  font-size: .9rem;
  font-weight: 700;
}

.etudes-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 20px;
}

.etudes-actions .btn {
  margin-top: 0;
}

@media (max-width: 768px) {
  nav .nav-etudes-menu {
    position: static;
    min-width: 0;
    margin-top: 6px;
    padding: 4px 0 4px 14px;
    background: transparent;
    border: 0;
    box-shadow: none;
  }

  .etudes-grid {
    grid-template-columns: 1fr;
  }
}

/* Responsive footer */
@media (max-width: 768px) {
  .footer-content {
    flex-direction: column;
    gap: 15px;
  }
}

/* Fin du fichier style.css */