/* ── NAVBAR PARTAGÉE ──────────────────────────────────────────────────────────
   Utilisée par toutes les pages avec le header standard (logo + liens + CTA).
   Ne pas dupliquer ces règles dans les CSS de page : les cas particuliers
   (ex: .topnav-cta qui diffère sur about.html) restent dans le CSS de la page.
── */

.topnav {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 1.5rem; height: 3.75rem;
  border-bottom: 1px solid rgba(255,255,255,0.06);
  background: rgba(7,17,31,0.85);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
}
.topnav-brand {
  display: flex; align-items: center; gap: 0.5rem;
  font-weight: 800; font-size: 1.25rem; color: #f8fafc; text-decoration: none;
}
.topnav-logo {
  width: 36px; height: 36px; border-radius: 50%; object-fit: contain;
  filter: drop-shadow(0 0 6px rgba(59,130,246,0.5));
}
.topnav-links { display: flex; align-items: center; gap: 0.25rem; }
.topnav-links a {
  color: #f1f5f9; text-decoration: none; font-size: 0.875rem;
  padding: 0.4rem 0.75rem; border-radius: 0.5rem;
  transition: color 0.2s, background 0.2s;
}
.topnav-links a:hover { color: #e2e8f0; background: rgba(255,255,255,0.07); }
.topnav-links a.active { color: #f1f5f9; background: rgba(255,255,255,0.07); position: relative; }
.topnav-links a.active::after {
  content: ''; position: absolute; bottom: -1px; left: 50%; transform: translateX(-50%);
  width: 18px; height: 2px; background: #3b82f6; border-radius: 2px;
}
.topnav-download {
  position: relative; overflow: hidden;
  background: linear-gradient(135deg, #3b82f6, #6366f1) !important;
  color: #fff !important; font-weight: 700 !important;
  border-radius: 0.55rem !important;
  box-shadow: 0 2px 12px rgba(59,130,246,0.35) !important;
}
.topnav-download:hover { filter: brightness(1.1); transform: translateY(-1px); }
.topnav-hamburger {
  display: none; flex-direction: column; justify-content: center; align-items: center;
  gap: 5px; width: 2.25rem; height: 2.25rem;
  background: none; border: none; cursor: pointer; padding: 0.25rem;
}
.topnav-hamburger span {
  display: block; width: 20px; height: 2px;
  background: #f1f5f9; border-radius: 2px; transition: all 0.25s;
}
.topnav-hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.topnav-hamburger.active span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.topnav-hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

@media (max-width: 700px) {
  .topnav-hamburger { display: flex; }
  .topnav-links {
    display: none; flex-direction: column; align-items: flex-start;
    position: fixed; top: 3.75rem; left: 0; right: 0;
    background: rgba(7,17,31,0.97); backdrop-filter: blur(12px);
    padding: 1rem; border-bottom: 1px solid rgba(255,255,255,0.07);
    gap: 0.25rem; z-index: 99;
  }
  .topnav-links.open { display: flex; }
  .topnav-links a { width: 100%; }
}