/* nav.css — Sticky header & navigation */

.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-nav);
  background: rgba(240, 253, 244, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--duration-base) var(--ease-out);
}

.site-header.is-scrolled {
  background: rgba(240, 253, 244, 0.98);
}

/* ─── Nav bar ─── */

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  height: var(--nav-height);
}

/* ─── Logo ─── */

.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
  transition: opacity var(--duration-fast) var(--ease-out);
}

.nav__logo:hover {
  opacity: 0.85;
}

.nav__logo-icon {
  flex-shrink: 0;
}

.nav__logo-text {
  font-size: var(--text-lg);
  font-weight: var(--font-bold);
  color: var(--color-text);
  letter-spacing: var(--tracking-tight);
}

/* ─── Desktop links ─── */

.nav__links {
  display: none;
  align-items: center;
  gap: var(--space-1);
  margin-left: var(--space-4);
}

@media (min-width: 768px) {
  .nav__links {
    display: flex;
  }
}

.nav__link {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-muted);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: color var(--duration-fast) var(--ease-out),
              background var(--duration-fast) var(--ease-out);
}

.nav__link:hover,
.nav__link.is-active {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.06);
}

/* ─── Nav actions ─── */

.nav__actions {
  display: none;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

@media (min-width: 768px) {
  .nav__actions {
    display: flex;
  }
}

/* ─── Mobile toggle ─── */

.nav__toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  padding: var(--space-2);
  margin-left: auto;
  border-radius: var(--radius-sm);
  transition: background var(--duration-fast) var(--ease-out);
}

@media (min-width: 768px) {
  .nav__toggle {
    display: none;
  }
}

.nav__toggle:hover {
  background: rgba(255, 255, 255, 0.06);
}

.nav__toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--duration-base) var(--ease-out),
              opacity var(--duration-base) var(--ease-out);
  transform-origin: center;
}

.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;
  transform: scaleX(0);
}

.nav__toggle[aria-expanded="true"] .nav__toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ─── Mobile menu ─── */

.nav__mobile {
  display: none;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-6) var(--space-6);
  border-top: 1px solid var(--color-border);
  background: rgba(240, 253, 244, 0.98);
}

.nav__mobile.is-open {
  display: flex;
}

.nav__mobile-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.nav__mobile-link {
  display: block;
  padding: var(--space-3) var(--space-2);
  font-size: var(--text-base);
  font-weight: var(--font-medium);
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: color var(--duration-fast), background var(--duration-fast);
}

.nav__mobile-link:hover {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.06);
}

.nav__mobile-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border);
}