/* ─── NAVIGATION ──────────────────────────────────────────────────────────── */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: oklch(from var(--color-bg) l c h / 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-divider);
  transition: box-shadow 0.3s ease, transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.site-header--scrolled {
  box-shadow: var(--shadow-sm);
}

.site-header--hidden {
  transform: translateY(-100%);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-8);
  height: 4rem;
}

/* Logo */
.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
  text-decoration: none;
}

.nav-logo__mark {
  width: 2rem;
  height: 2rem;
  color: var(--color-primary);
}

.nav-logo__wordmark {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--color-text);
}

/* Desktop nav links */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: color var(--transition-interactive), background var(--transition-interactive);
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-text);
  background: var(--color-surface-offset);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.nav-dropdown__trigger {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: color var(--transition-interactive), background var(--transition-interactive);
  white-space: nowrap;
  background: none;
  border: none;
  font-family: var(--font-body);
}

.nav-dropdown__trigger:hover {
  color: var(--color-text);
  background: var(--color-surface-offset);
}

.nav-dropdown__trigger svg {
  transition: transform 0.2s ease;
  flex-shrink: 0;
}

.nav-dropdown:hover .nav-dropdown__trigger svg,
.nav-dropdown.open .nav-dropdown__trigger svg {
  transform: rotate(180deg);
}

.nav-dropdown__menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-2);
  min-width: 200px;
  opacity: 0;
  visibility: hidden;
  transform: translateX(-50%) translateY(-6px);
  transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s;
  list-style: none;
  z-index: 200;
}

.nav-dropdown:hover .nav-dropdown__menu,
.nav-dropdown.open .nav-dropdown__menu {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.nav-dropdown__menu a {
  display: block;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: color var(--transition-interactive), background var(--transition-interactive);
}

.nav-dropdown__menu a:hover {
  color: var(--color-text);
  background: var(--color-surface-offset);
}

/* Nav actions */
.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

/* Hamburger */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 2rem;
  height: 2rem;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-interactive);
}
.nav-hamburger:hover { background: var(--color-surface-offset); }
.nav-hamburger span {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile drawer */
.nav-mobile {
  display: none;
  position: fixed;
  inset: 4rem 0 0 0;
  background: var(--color-bg);
  padding: var(--space-6) clamp(var(--space-6), 5vw, var(--space-16));
  z-index: 90;
  overflow-y: auto;
  border-top: 1px solid var(--color-divider);
}
.nav-mobile.open { display: block; }

.nav-mobile__links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  margin-bottom: var(--space-8);
}

.nav-mobile__links a,
.nav-mobile__links summary {
  display: block;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  list-style: none;
  cursor: pointer;
}

.nav-mobile__links a:hover { color: var(--color-text); background: var(--color-surface-offset); }

.nav-mobile__sub {
  padding-left: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  margin-top: var(--space-1);
}

.nav-mobile__actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

@media (max-width: 900px) {
  .nav-links,
  .nav-desktop-only { display: none; }
  .nav-hamburger { display: flex; }
}

@media (min-width: 901px) {
  .nav-mobile { display: none !important; }
}