:root {
  --bg: #050817;
  --bg-alt: #0b1020;
  --card-bg: #12172a;
  --primary: #3b82f6;
  --primary-soft: rgba(59, 130, 246, 0.12);
  --text: #e5e7eb;
  --text-soft: #9ca3af;
  --border: #1f2937;
  --accent: #22c55e;
  --danger: #ef4444;
  --radius-lg: 18px;
  --radius-xl: 28px;
  --shadow-soft: 0 18px 35px rgba(0, 0, 0, 0.35);
}

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

html,
body {
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: radial-gradient(circle at top, #161b33 0, var(--bg) 45%, #020617 100%);
  color: var(--text);
  scroll-behavior: smooth;
}

/* layout généraux */
.container {
  width: 100%;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

.section {
  padding: 4.5rem 0;
}

.section-alt {
  background: radial-gradient(circle at top left, #111827 0, #020617 55%, #020617 100%);
}

/* header et navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(18px);
  background: linear-gradient(to bottom, rgba(3, 7, 18, 0.92), rgba(3, 7, 18, 0.7));
  border-bottom: 1px solid rgba(31, 41, 55, 0.7);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 0.5rem;
}

.logo {
  display: flex;
  align-items: baseline;
  gap: 0.3rem;
}

.logo-mark {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #0b1120;
  font-weight: 800;
  padding: 0.18rem 0.5rem;
  border-radius: 999px;
  letter-spacing: 0.06em;
  font-size: 0.85rem;
  text-transform: uppercase;
}

.logo-text {
  font-weight: 600;
  letter-spacing: 0.04em;
  font-size: 0.9rem;
  color: #e5e7eb;
}

.nav {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  font-size: 0.9rem;
}

.nav a {
  color: var(--text-soft);
  text-decoration: none;
  padding: 0.3rem 0.2rem;
  transition: color 0.2s ease, transform 0.2s ease;
}

.nav a:hover {
  color: var(--text);
  transform: translateY(-1px);
}

.btn-nav {
  border-radius: 999px;
  border: 1px solid rgba(148, 163, 184, 0.7);
  padding: 0.35rem 0.75rem;
}

/* hero */
.hero {
  padding: 4rem 0 3.5rem;
}

.hero-grid {
  display: grid;
  gap: 2rem;
}

.hero-text h1 {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  margin: 0 0 0.75rem;
  line-height: 1.2;
}

.hero-subtitle {
  margin: 0 0 1.5rem;
  color: var(--text-soft);
  max-width: 34rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.hero-note {
  font-size: 0.85rem;
  color: var(--text-soft);
}

.hero-card {
  background: radial-gradient(circle at top left, #1f2937 0, #020617 70%);
  border-radius: var(--radius-xl);
  padding: 1.5rem 1.6rem;
  border: 1px solid rgba(55, 65, 81, 0.9);
  box-shadow: var(--shadow-soft);
}

.hero-card h2 {
  font-size: 1.1rem;
  margin-top: 0;
  margin-bottom: 0.9rem;
}

.hero-card ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--text-soft);
  font-size: 0.9rem;
}

.hero-card li + li {
  margin-top: 0.3rem;
}

/* boutons */
.btn-primary,
.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.1rem;
  border-radius: 999px;
  font-size: 0.9rem;
  text-decoration: none;
  cursor: pointer;
  border: none;
  outline: none;
  transition:
    transform 0.15s ease,
    box-shadow 0.15s ease,
    background 0.15s ease,
    border-color 0.15s ease,
    color 0.15s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--accent));
  color: #020617;
  font-weight: 600;
  box-shadow: 0 14px 30px rgba(37, 99, 235, 0.45);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 40px rgba(37, 99, 235, 0.6);
}

.btn-secondary {
  background: rgba(15, 23, 42, 0.9);
  color: var(--text-soft);
  border: 1px solid rgba(148, 163, 184, 0.7);
}

.btn-secondary:hover {
  color: var(--text);
  background: rgba(15, 23, 42, 1);
}

.btn-full {
  width: 100%;
}

/* titres de section */
.section-title {
  font-size: 1.5rem;
  margin: 0 0 0.6rem;
}

.section-intro {
  margin: 0 0 2.2rem;
  max-width: 38rem;
  color: var(--text-soft);
  font-size: 0.95rem;
}

/* cartes */
.cards-grid {
  display: grid;
  gap: 1.5rem;
}

.card {
  background: linear-gradient(145deg, rgba(15, 23, 42, 0.96), rgba(15, 23, 42, 0.98));
  border-radius: var(--radius-lg);
  padding: 1.3rem 1.4rem;
  border: 1px solid rgba(51, 65, 85, 0.9);
  box-shadow: var(--shadow-soft);
}

.card h3 {
  margin-top: 0;
  margin-bottom: 0.5rem;
  font-size: 1.05rem;
}

.card p {
  margin-top: 0;
  margin-bottom: 0.7rem;
  font-size: 0.92rem;
  color: var(--text-soft);
}

.card ul {
  margin: 0;
  padding-left: 1.1rem;
  font-size: 0.9rem;
  color: var(--text-soft);
}

.card ul li + li {
  margin-top: 0.25rem;
}

.tag {
  margin-top: 0.35rem;
  font-size: 0.85rem;
  color: #a5b4fc;
}

/* à propos */
.about-grid {
  display: grid;
  gap: 1.7rem;
}

.about-card {
  background: radial-gradient(circle at top left, #111827 0, #020617 70%);
  border-radius: var(--radius-lg);
  padding: 1.3rem 1.4rem;
  border: 1px solid rgba(55, 65, 81, 0.9);
  box-shadow: var(--shadow-soft);
}

.about-card h3 {
  margin-top: 0;
  margin-bottom: 0.7rem;
}

.about-card ul {
  margin: 0;
  padding-left: 1.1rem;
  font-size: 0.9rem;
  color: var(--text-soft);
}

.about-card li + li {
  margin-top: 0.3rem;
}

/* contact */
.contact-grid {
  display: grid;
  gap: 1.8rem;
  align-items: flex-start;
}

.contact-form {
  background: rgba(15, 23, 42, 0.97);
  border-radius: var(--radius-lg);
  padding: 1.4rem 1.5rem;
  border: 1px solid rgba(55, 65, 81, 0.95);
  box-shadow: var(--shadow-soft);
}

.form-row {
  margin-bottom: 0.9rem;
}

label {
  display: block;
  font-size: 0.82rem;
  margin-bottom: 0.25rem;
  color: var(--text-soft);
}

input,
textarea {
  width: 100%;
  border-radius: 0.7rem;
  border: 1px solid rgba(55, 65, 81, 0.95);
  padding: 0.5rem 0.65rem;
  background: #020617;
  color: var(--text);
  font-size: 0.9rem;
}

input:focus,
textarea:focus {
  outline: 1px solid rgba(59, 130, 246, 0.7);
  border-color: rgba(59, 130, 246, 0.9);
}

.form-note {
  margin-top: 0.6rem;
  font-size: 0.8rem;
  color: var(--text-soft);
}

/* footer */
.footer {
  padding: 1.2rem 0 1.4rem;
  border-top: 1px solid rgba(31, 41, 55, 0.9);
  background: #020617;
}

.footer-content {
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-soft);
}

.footer-small {
  margin-top: 0.25rem;
  font-size: 0.76rem;
}

/* responsive */
@media (min-width: 768px) {
  .hero-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    align-items: center;
  }

  .cards-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .about-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  }

  .contact-grid {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  }
}

@media (max-width: 640px) {
  .nav {
    display: none; /* menu caché sur mobile pour l’instant */
  }

  .hero {
    padding-top: 3rem;
  }

  .section {
    padding: 3.2rem 0;
  }
}