.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background: rgba(247, 249, 252, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  min-height: var(--header-h);
}
.nav-desktop { display: none; }
.nav-list { display: flex; align-items: center; gap: 0.15rem; }
.nav-item { position: relative; }
.nav-link, .nav-toggle-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  min-height: 2.5rem;
  padding: 0.4rem 0.65rem;
  border: 0;
  background: transparent;
  font-weight: 600;
  color: var(--color-navy-deep);
  text-decoration: none !important;
  cursor: pointer;
}
.nav-link:hover, .nav-toggle-btn:hover, .nav-link[aria-current="page"] { color: var(--color-navy); }

.mega {
  position: absolute;
  left: 0;
  top: calc(100% + 0.35rem);
  min-width: 16rem;
  background: var(--color-white);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-soft);
  padding: var(--space-3);
  display: none;
}
.nav-item.open > .mega, .nav-item:focus-within > .mega { display: grid; gap: 0.25rem; }
.mega a {
  display: block;
  padding: 0.45rem 0.55rem;
  text-decoration: none !important;
  border-radius: var(--radius);
  font-weight: 500;
}
.mega a:hover, .mega a:focus-visible { background: var(--color-sand); }

.header-actions { display: flex; align-items: center; gap: var(--space-2); }
.menu-btn {
  display: inline-flex;
  min-height: 2.5rem;
  min-width: 2.5rem;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  background: var(--color-white);
  border-radius: var(--radius);
}
.mobile-nav {
  display: none;
  border-top: 1px solid var(--color-border);
  background: var(--color-white);
  padding: var(--space-4);
}
.mobile-nav.open { display: block; }
.mobile-nav details { border-bottom: 1px solid var(--color-border); padding: 0.5rem 0; }
.mobile-nav a { display: block; padding: 0.4rem 0; text-decoration: none !important; font-weight: 500; }
.mobile-nav summary { font-weight: 700; cursor: pointer; }

@media (min-width: 1024px) {
  .nav-desktop { display: block; }
  .menu-btn { display: none; }
}