:root {
  --fond: #101810;
  --carte: #1d2a1e;
  --vert: #3fa34d;
  --vert-clair: #7ee787;
  --or: #ffd166;
  --texte: #f4f4f4;
  --gris: #b8c2b8;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  scroll-behavior: smooth;
}

body {
  font-family: Arial, sans-serif;
  background: var(--fond);
  color: var(--texte);
  line-height: 1.6;
}

header {
  position: relative;

  min-height: 55vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 30px;

  background:
    linear-gradient(#0008, #000b),
    url("https://images.unsplash.com/photo-1500534623283-312aade485b7?auto=format&fit=crop&w=1800&q=80")
    center / cover;
}

header h1 {
  color: var(--or);
  font-size: clamp(2.5rem, 8vw, 5rem);
  text-shadow: 4px 4px #000;
}

header p {
  max-width: 700px;
  margin: 15px auto;
  font-size: 1.2rem;
}

nav {
  position: sticky;
  top: 0;
  z-index: 5;

  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;

  padding: 14px;
  background: #172318;
  border-bottom: 2px solid var(--vert);
}

nav a {
  color: white;
  text-decoration: none;
  padding: 9px 14px;
  border-radius: 6px;
}

nav a:hover,
nav a.active {
  background: var(--vert);
}

main {
  width: min(1100px, 92%);
  margin: auto;
}

section {
  padding: 60px 0;
  text-align: center;
}

h2 {
  color: var(--or);
  font-size: 2.3rem;
  margin-bottom: 12px;
}

h3 {
  color: var(--vert-clair);
  margin-bottom: 8px;
}

p {
  color: var(--gris);
}

.introduction {
  max-width: 800px;
  margin: 0 auto 28px;
}

.cartes {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(245px, 1fr));
  gap: 20px;
  text-align: left;
}

.carte {
  background: var(--carte);
  border: 1px solid #315535;
  border-radius: 12px;
  padding: 22px;
  transition: 0.3s;
}

.carte:hover {
  transform: translateY(-5px);
  border-color: var(--vert);
}

.bouton {
  position: absolute;
  top: 0;
  right: 0;
  z-index: 20;

  display: inline-block;
  padding: 14px 24px;

  background: linear-gradient(
    135deg,
    #5826b9,
    #8d55ff 50%,
    #237fa8
  );

  color: white;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: bold;

  border: 3px solid #bca0ff;
  border-radius: 4px;

  box-shadow:
    0 0 8px #8f5cff,
    0 0 20px rgba(102, 53, 255, 0.8),
    inset 0 0 10px rgba(255, 255, 255, 0.25);

  transition: 0.25s ease;
}

.bouton:hover {
  transform: translateY(-4px) scale(1.05);

  background: linear-gradient(
    135deg,
    #7041ff,
    #a66cff,
    #00aeca
  );

  box-shadow:
    0 0 12px #a77aff,
    0 0 30px #7041ff,
    0 0 50px rgba(0, 217, 255, 0.7);
}

footer {
  text-align: center;
  padding: 30px;
  background: #0b100b;
  color: var(--gris);
}

@media (max-width: 600px) {
  nav {
    justify-content: flex-start;
    overflow-x: auto;
  }

  section {
    padding: 40px 0;
  }

  h2 {
    font-size: 2rem;
  }

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

  .bouton {
    top: 15px;
    right: 15px;
    padding: 10px 14px;
    font-size: 11px;
  }
}

header {
  position: relative !important;
}

header .bouton {
  position: absolute !important;
  top: 20px !important;
  right: 20px !important;
  z-index: 999 !important;
}