/* =========================================================================
   ELAN-IT — site institutionnel — feuille de style
   Charte sobre corporate sur-mesure (SD-E03) · mobile-first (SD-E05)
   Aucune dépendance, aucune police distante (SD-E01).
   Couleurs = placeholders à substituer par la charte ELAN-IT définitive.
   ========================================================================= */

/* ---- Design tokens ---------------------------------------------------- */
:root {
  --c-bg: #ffffff;
  --c-surface: #f4f6f8;
  --c-surface-2: #eaeef3;
  --c-text: #1a2230;
  --c-muted: #54637a;
  --c-accent: #1f6feb;
  --c-accent-strong: #0b3d91;
  --c-accent-contrast: #ffffff;
  --c-border: #e2e8f0;
  --c-shadow: rgba(16, 32, 64, 0.08);

  --font: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --maxw: 72rem;
  --radius: 12px;
  --radius-sm: 8px;
  --gap: clamp(1rem, 3vw, 2rem);
  --nav-h: 4rem;
  --transition: 180ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --c-bg: #0e1420;
    --c-surface: #161d2b;
    --c-surface-2: #1e2637;
    --c-text: #eef2f8;
    --c-muted: #a2b0c4;
    --c-accent: #5b9bff;
    --c-accent-strong: #7fb0ff;
    --c-accent-contrast: #0b1220;
    --c-border: #26304180;
    --c-shadow: rgba(0, 0, 0, 0.4);
  }
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  font-size: clamp(1rem, 0.95rem + 0.3vw, 1.125rem);
  line-height: 1.6;
  color: var(--c-text);
  background: var(--c-bg);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3 { line-height: 1.2; font-weight: 700; letter-spacing: -0.01em; }
h1 { font-size: clamp(2rem, 1.4rem + 3vw, 3.4rem); margin: 0 0 1rem; }
h2 { font-size: clamp(1.5rem, 1.1rem + 1.8vw, 2.3rem); margin: 0 0 0.75rem; }
h3 { font-size: 1.2rem; margin: 0 0 0.5rem; }
p { margin: 0 0 1rem; }
a { color: var(--c-accent-strong); }

em { font-style: normal; color: var(--c-accent-strong); }

.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: clamp(1rem, 4vw, 2.5rem); }

/* Ancres compensées par la nav fixe */
:target { scroll-margin-top: calc(var(--nav-h) + 1rem); }
section[id], footer [id] { scroll-margin-top: calc(var(--nav-h) + 1rem); }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 1000;
  background: var(--c-accent-strong); color: #fff; padding: 0.6rem 1rem; border-radius: 0 0 var(--radius-sm) 0;
}
.skip-link:focus { left: 0; }

:focus-visible { outline: 3px solid var(--c-accent); outline-offset: 2px; border-radius: 4px; }

/* ---- Boutons ---------------------------------------------------------- */
.btn {
  display: inline-block; text-decoration: none; font-weight: 600;
  padding: 0.7rem 1.3rem; border-radius: var(--radius-sm);
  border: 1.5px solid transparent; cursor: pointer;
  transition: transform var(--transition), background var(--transition), border-color var(--transition);
}
.btn:hover { transform: translateY(-1px); }
.btn-sm { padding: 0.45rem 0.9rem; font-size: 0.95rem; }
.btn-primary { background: var(--c-accent-strong); color: var(--c-accent-contrast); }
.btn-primary:hover { background: var(--c-accent); }
.btn-ghost { background: transparent; color: var(--c-text); border-color: var(--c-border); }
.btn-ghost:hover { border-color: var(--c-accent); color: var(--c-accent-strong); }

/* ---- En-tête / navigation --------------------------------------------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--c-bg) 88%, transparent);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--c-border);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; min-height: var(--nav-h); }

.brand { display: inline-flex; align-items: center; gap: 0.5rem; text-decoration: none; color: var(--c-text); font-weight: 800; letter-spacing: 0.02em; }
.brand-mark { color: var(--c-accent); }
.brand-name { font-size: 1.15rem; }

.nav-toggle {
  display: inline-flex; flex-direction: column; justify-content: center; gap: 5px;
  width: 44px; height: 44px; padding: 10px; background: none; border: 1px solid var(--c-border);
  border-radius: var(--radius-sm); cursor: pointer;
}
.nav-toggle-bar { display: block; height: 2px; width: 100%; background: var(--c-text); transition: transform var(--transition), opacity var(--transition); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.primary-nav { position: absolute; inset: var(--nav-h) 0 auto 0; background: var(--c-bg); border-bottom: 1px solid var(--c-border); max-height: 0; overflow: hidden; transition: max-height var(--transition); }
.primary-nav.open { max-height: 24rem; }
.primary-nav ul { list-style: none; margin: 0; padding: 0.5rem clamp(1rem, 4vw, 2.5rem) 1rem; display: flex; flex-direction: column; gap: 0.25rem; }
.primary-nav a { display: block; padding: 0.7rem 0.25rem; text-decoration: none; color: var(--c-text); font-weight: 600; border-radius: var(--radius-sm); }
.primary-nav a:hover { color: var(--c-accent-strong); }
.nav-cta { margin-top: 0.5rem; text-align: center; }

/* ---- Hero ------------------------------------------------------------- */
.hero {
  padding: clamp(3rem, 8vw, 6.5rem) 0 clamp(2.5rem, 6vw, 5rem);
  background:
    radial-gradient(120% 90% at 80% -10%, color-mix(in srgb, var(--c-accent) 22%, transparent), transparent 60%),
    linear-gradient(180deg, var(--c-surface), var(--c-bg));
  border-bottom: 1px solid var(--c-border);
}
.eyebrow { text-transform: uppercase; letter-spacing: 0.12em; font-size: 0.8rem; font-weight: 700; color: var(--c-accent-strong); margin: 0 0 0.75rem; }
.hero .lead { font-size: clamp(1.05rem, 1rem + 0.6vw, 1.35rem); color: var(--c-muted); max-width: 42rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 1.75rem; }

/* ---- Sections --------------------------------------------------------- */
.section { padding: clamp(3rem, 7vw, 5.5rem) 0; }
.section-alt { background: var(--c-surface); border-block: 1px solid var(--c-border); }
.section-head { max-width: 46rem; margin-bottom: clamp(1.5rem, 4vw, 2.5rem); }
.section-intro { color: var(--c-muted); font-size: 1.05rem; margin: 0; }

/* ---- Cartes ----------------------------------------------------------- */
.cards { display: grid; gap: var(--gap); grid-template-columns: 1fr; }
@media (min-width: 40rem) { .cards-3 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 64rem) { .cards-3 { grid-template-columns: repeat(3, 1fr); } }

.card {
  background: var(--c-bg); border: 1px solid var(--c-border); border-radius: var(--radius);
  padding: 1.5rem; box-shadow: 0 1px 2px var(--c-shadow);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}
.card:hover { transform: translateY(-3px); box-shadow: 0 10px 30px var(--c-shadow); border-color: color-mix(in srgb, var(--c-accent) 40%, var(--c-border)); }
.card-icon { font-size: 1.8rem; margin-bottom: 0.6rem; }
.card p { margin: 0; color: var(--c-muted); }
.card p strong { color: var(--c-text); }

.card-usecase h3 { color: var(--c-accent-strong); }
.usecase-what { margin-bottom: 0.75rem !important; }
.usecase-benefit { color: var(--c-text) !important; font-weight: 600; padding-top: 0.75rem; border-top: 1px dashed var(--c-border); }
.card-cta-inline { background: linear-gradient(180deg, var(--c-surface-2), var(--c-bg)); }
.card-cta-inline p { color: var(--c-muted); }

/* ---- Confiance -------------------------------------------------------- */
.trust-grid { display: grid; gap: var(--gap); grid-template-columns: 1fr; }
@media (min-width: 40rem) { .trust-grid { grid-template-columns: repeat(2, 1fr); } }
.trust-item { padding-left: 1rem; border-left: 3px solid var(--c-accent); }
.trust-item h3 { color: var(--c-text); }
.trust-item p { margin: 0; color: var(--c-muted); }

/* ---- À propos & contact ----------------------------------------------- */
.about-contact { display: grid; gap: var(--gap); grid-template-columns: 1fr; align-items: start; }
@media (min-width: 56rem) { .about-contact { grid-template-columns: 1.4fr 1fr; } }
.about p { color: var(--c-muted); }
.about p strong { color: var(--c-text); }
.contact-card {
  background: var(--c-bg); border: 1px solid var(--c-border); border-radius: var(--radius);
  padding: 1.75rem; box-shadow: 0 8px 30px var(--c-shadow); position: sticky; top: calc(var(--nav-h) + 1rem);
}
.contact-card h3 { color: var(--c-accent-strong); }
.contact-card .btn { margin-top: 0.5rem; }
.contact-note { margin: 0.75rem 0 0; font-size: 0.9rem; color: var(--c-muted); }

/* ---- Pied de page ----------------------------------------------------- */
.site-footer { background: var(--c-surface-2); border-top: 1px solid var(--c-border); padding: clamp(2rem, 5vw, 3rem) 0 2rem; }
.footer-inner { display: flex; flex-wrap: wrap; gap: 1rem 2rem; justify-content: space-between; align-items: start; }
.footer-brand { font-weight: 800; }
.footer-tagline { font-weight: 400; color: var(--c-muted); margin: 0.35rem 0 0; font-size: 0.95rem; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 0.5rem 1.25rem; }
.footer-nav a { text-decoration: none; color: var(--c-muted); font-weight: 600; }
.footer-nav a:hover { color: var(--c-accent-strong); }

.legal { margin-top: 2rem; padding-top: 1.5rem; border-top: 1px solid var(--c-border); color: var(--c-muted); font-size: 0.9rem; }
.legal-title { font-size: 1rem; color: var(--c-text); margin-bottom: 0.5rem; }
.legal p { margin: 0 0 0.5rem; }
.copyright { margin-top: 0.5rem; }

/* ---- Préférences de mouvement ----------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .btn:hover, .card:hover { transform: none; }
}