:root {
  --ink: #1a1a2e;
  --paper: #f8f6f1;
  --accent: #2d5a3d;
  --accent-light: #3a7550;
  --warm: #e8e0d4;
  --warm-dark: #d4c9b8;
  --text: #3a3a4a;
  --text-light: #6b6b7b;
  --white: #ffffff;
  --shadow-sm: 0 1px 3px rgba(26,26,46,0.06);
  --shadow-md: 0 4px 16px rgba(26,26,46,0.08);
  --shadow-lg: 0 8px 32px rgba(26,26,46,0.12);
  --radius: 6px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: 'DM Sans', sans-serif;
  color: var(--text);
  background: var(--paper);
  line-height: 1.7;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
}

/* ─── NAV ─── */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(248,246,241,0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(26,26,46,0.06);
  transition: box-shadow 0.3s;
}
nav.scrolled { box-shadow: var(--shadow-sm); }
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.9rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.nav-brand {
  font-family: 'DM Serif Display', serif;
  font-size: 1.15rem;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.02em;
}
.nav-links { display: flex; gap: 2rem; align-items: center; }
.nav-links a {
  color: var(--text-light);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}
.nav-links a:hover { color: var(--ink); }
.nav-cta {
  background: var(--accent) !important;
  color: var(--white) !important;
  padding: 0.5rem 1.2rem;
  border-radius: var(--radius);
  font-weight: 600 !important;
  transition: background 0.2s !important;
}
.nav-cta:hover { background: var(--accent-light) !important; }

.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.5rem; }
.nav-toggle span {
  display: block; width: 22px; height: 2px; background: var(--ink);
  margin: 5px 0; transition: all 0.3s; border-radius: 1px;
}

/* ─── HERO ─── */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 8rem 2rem 4rem;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  right: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(45,90,61,0.06) 0%, transparent 70%);
  border-radius: 50%;
  pointer-events: none;
}
.hero-inner {
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
}
.hero-label {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 1.5rem;
  position: relative;
  padding-left: 2rem;
}
.hero-label::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  width: 1.2rem;
  height: 2px;
  background: var(--accent);
}
.hero h1 {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  color: var(--ink);
  line-height: 1.15;
  letter-spacing: -0.03em;
  max-width: 780px;
  margin-bottom: 1.5rem;
}
.hero h1 em {
  font-style: normal;
  color: var(--accent);
}
.hero-text {
  font-size: 1.15rem;
  color: var(--text-light);
  max-width: 560px;
  margin-bottom: 2.5rem;
  line-height: 1.8;
}
.hero-actions { display: flex; gap: 1rem; flex-wrap: wrap; }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.8rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.25s;
  border: none;
  font-family: inherit;
}
.btn-primary {
  background: var(--accent);
  color: var(--white);
}
.btn-primary:hover { background: var(--accent-light); transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-secondary {
  background: transparent;
  color: var(--text);
  border: 1.5px solid var(--warm-dark);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

/* ─── SECTIONS ─── */
section { padding: 5rem 2rem; }
.section-inner { max-width: 1100px; margin: 0 auto; }
.section-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.75rem;
}
.section-title {
  font-family: 'DM Serif Display', serif;
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  color: var(--ink);
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
  line-height: 1.2;
}
.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-light);
  max-width: 560px;
  margin-bottom: 3rem;
}

/* ─── PROBLEME ─── */
.problems { background: var(--ink); color: var(--white); }
.problems .section-label { color: rgba(255,255,255,0.5); }
.problems .section-title { color: var(--white); }
.problems .section-subtitle { color: rgba(255,255,255,0.6); }
.problem-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}
.problem-card {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--radius);
  padding: 2rem;
  transition: background 0.3s;
}
.problem-card:hover { background: rgba(255,255,255,0.08); }
.problem-icon {
  font-size: 1.6rem;
  margin-bottom: 1rem;
  display: block;
}
.problem-card h3 {
  font-family: 'DM Serif Display', serif;
  font-size: 1.15rem;
  margin-bottom: 0.6rem;
  color: var(--white);
}
.problem-card p {
  font-size: 0.92rem;
  color: rgba(255,255,255,0.55);
  line-height: 1.7;
}

/* ─── METHODE ─── */
.method-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
  counter-reset: step;
}
.step {
  position: relative;
  padding: 2rem 1.5rem;
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  border: 1px solid rgba(26,26,46,0.04);
  transition: box-shadow 0.3s, transform 0.3s;
}
.step:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.step::before {
  counter-increment: step;
  content: counter(step);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.2rem;
  height: 2.2rem;
  background: var(--accent);
  color: var(--white);
  border-radius: 50%;
  font-size: 0.85rem;
  font-weight: 700;
  margin-bottom: 1.2rem;
}
.step h3 {
  font-family: 'DM Serif Display', serif;
  font-size: 1.1rem;
  color: var(--ink);
  margin-bottom: 0.5rem;
}
.step p {
  font-size: 0.9rem;
  color: var(--text-light);
  line-height: 1.7;
}

/* ─── REFERENCES ─── */
.ref-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}
.ref-card {
  padding: 2rem;
  background: var(--white);
  border-radius: var(--radius);
  border: 1px solid rgba(26,26,46,0.06);
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.3s, transform 0.3s;
}
.ref-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.ref-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  background: rgba(45,90,61,0.08);
  padding: 0.25rem 0.7rem;
  border-radius: 3px;
  margin-bottom: 1rem;
}
.ref-card h3 {
  font-family: 'DM Serif Display', serif;
  font-size: 1.1rem;
  color: var(--ink);
  margin-bottom: 0.6rem;
}
.ref-card p {
  font-size: 0.9rem;
  color: var(--text-light);
  line-height: 1.7;
}

/* ─── ABOUT ─── */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: start;
}
.about-text p {
  margin-bottom: 1.2rem;
  color: var(--text);
}
.about-facts {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}
.fact {
  padding: 1.5rem;
  background: var(--white);
  border-radius: var(--radius);
  border: 1px solid rgba(26,26,46,0.06);
  text-align: center;
}
.fact-number {
  font-family: 'DM Serif Display', serif;
  font-size: 2rem;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 0.3rem;
}
.fact-label {
  font-size: 0.82rem;
  color: var(--text-light);
  font-weight: 500;
}

/* ─── CONTACT ─── */
.contact {
  background: var(--ink);
  color: var(--white);
  text-align: center;
}
.contact .section-label { color: rgba(255,255,255,0.5); }
.contact .section-title { color: var(--white); }
.contact .section-subtitle {
  color: rgba(255,255,255,0.6);
  margin-left: auto;
  margin-right: auto;
}
.contact-email {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: 'DM Serif Display', serif;
  font-size: clamp(1.3rem, 2.5vw, 1.8rem);
  color: var(--white);
  text-decoration: none;
  padding: 1rem 2rem;
  border: 1.5px solid rgba(255,255,255,0.2);
  border-radius: var(--radius);
  transition: all 0.3s;
  margin-bottom: 2rem;
}
.contact-email:hover {
  border-color: rgba(255,255,255,0.5);
  background: rgba(255,255,255,0.05);
}
.contact-note {
  font-size: 0.95rem;
  color: rgba(255,255,255,0.45);
  margin-top: 1.5rem;
}

/* ─── FOOTER ─── */
footer {
  background: var(--ink);
  border-top: 1px solid rgba(255,255,255,0.06);
  padding: 1.5rem 2rem;
  text-align: center;
}
footer p {
  font-size: 0.82rem;
  color: rgba(255,255,255,0.3);
}
footer a { color: rgba(255,255,255,0.4); text-decoration: none; }
footer a:hover { color: rgba(255,255,255,0.6); }

/* ─── ANIMATIONS ─── */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ─── RESPONSIVE ─── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(248,246,241,0.98);
    backdrop-filter: blur(12px);
    padding: 1.5rem 2rem;
    gap: 1.2rem;
    border-bottom: 1px solid rgba(26,26,46,0.06);
  }
  .nav-toggle { display: block; }
  .hero { min-height: auto; padding: 7rem 1.5rem 3rem; }
  section { padding: 3.5rem 1.5rem; }
  .about-content { grid-template-columns: 1fr; gap: 2rem; }
  .hero-actions { flex-direction: column; }
  .btn { justify-content: center; }
}