/**
 * navigation.css — Header, nav, mobile menu, sticky behaviour.
 */

.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  width: 100%;
  /* Frosted glass — translucent deep-green with a blurred backdrop */
  background-color: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  border-bottom: 1px solid var(--glass-border);
  color: var(--color-text-inverse);
  transition: background-color var(--transition-base),
              box-shadow var(--transition-base),
              border-color var(--transition-base);
}

/* Once scrolled, the glass deepens and lifts off the page */
.site-header.is-sticky {
  background-color: rgba(15, 33, 25, 0.82);
  box-shadow: var(--shadow-lg);
  border-bottom-color: transparent;
}

/* No-backdrop-filter fallback: opaque green so text stays legible */
@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
  .site-header { background-color: var(--color-primary); }
}

/* Transparent variant for pages with a hero behind the header */
.site-header--transparent {
  position: fixed;
  background-color: transparent;
  -webkit-backdrop-filter: none;
  backdrop-filter: none;
  border-bottom-color: transparent;
}
.site-header--transparent.is-sticky {
  position: fixed;
  background-color: rgba(15, 33, 25, 0.82);
  -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  backdrop-filter: blur(var(--glass-blur)) saturate(140%);
  box-shadow: var(--shadow-lg);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  padding-block: var(--space-4);
}

/* Branding */
.site-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-text-inverse);
}
.site-brand__logo { height: 36px; width: auto; }
.site-brand__name {
  font-family: var(--font-display);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-black);
  letter-spacing: var(--letter-spacing-tight);
  color: var(--color-text-inverse);
}

/* Primary nav */
.primary-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  margin: 0;
  padding: 0;
  list-style: none;
}
.primary-nav__list li { margin: 0; }
.primary-nav a {
  position: relative;
  color: var(--color-text-inverse);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-base);
  padding-block: var(--space-2);
  transition: color var(--transition-fast);
}
/* Animated gold underline that grows from the centre */
.primary-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  border-radius: var(--radius-full);
  background: var(--gradient-accent);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition-base);
}
.primary-nav a:hover,
.primary-nav .current-menu-item > a,
.primary-nav .current_page_item > a {
  color: var(--color-accent);
}
.primary-nav a:hover::after,
.primary-nav .current-menu-item > a::after,
.primary-nav .current_page_item > a::after {
  transform: scaleX(1);
}

.site-header__actions { display: flex; align-items: center; gap: var(--space-4); }

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  background: none;
  border: none;
}
.nav-toggle__bar {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text-inverse);
  transition: transform var(--transition-base), opacity var(--transition-base);
}
.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); }

/* Mobile menu */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }

  .primary-nav {
    position: fixed;
    inset: 0;
    top: 0;
    z-index: var(--z-overlay);
    background-color: var(--color-primary);
    transform: translateY(-100%);
    transition: transform var(--transition-base);
    padding: var(--space-24) var(--space-6) var(--space-8);
    overflow-y: auto;
  }
  .primary-nav.is-open { transform: translateY(0); }

  .primary-nav__list {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }
  .primary-nav a {
    font-family: var(--font-display);
    font-size: var(--font-size-2xl);
  }
  .primary-nav a::after { display: none; }

  /* Frost the mobile overlay to match the glass header */
  .primary-nav {
    background-color: rgba(15, 33, 25, 0.92);
    -webkit-backdrop-filter: blur(var(--glass-blur));
    backdrop-filter: blur(var(--glass-blur));
  }
}