/* ============================================
   Component: Site Header
   ============================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--color-border);
}

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

.site-header__brand {
  display: flex;
  align-items: center;
  color: var(--color-text);
}

.site-header__logo {
  height: 56px;
  width: auto;
  object-fit: contain;
  flex-shrink: 0;
  display: block;
}

.site-header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.site-header__nav a {
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  position: relative;
  padding: var(--space-1) 0;
}

.site-header__nav a:hover {
  color: var(--color-primary);
}

.site-header__nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -4px;
  height: 2px;
  background: var(--color-secondary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.18s ease;
}

.site-header__nav a:hover::after {
  transform: scaleX(1);
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* ============================================
   Hamburger button (hidden on desktop)
   ============================================ */

.site-header__menu-toggle {
  display: none;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: transparent;
  cursor: pointer;
  position: relative;
}

.site-header__menu-icon,
.site-header__menu-icon::before,
.site-header__menu-icon::after {
  display: block;
  position: absolute;
  left: 50%;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform 0.25s ease, top 0.25s ease, opacity 0.2s ease;
}

.site-header__menu-icon {
  top: 50%;
  transform: translate(-50%, -50%);
}

.site-header__menu-icon::before {
  content: "";
  top: -7px;
  transform: translateX(-50%);
}

.site-header__menu-icon::after {
  content: "";
  top: 7px;
  transform: translateX(-50%);
}

/* Hamburger → X when open */
.site-header[data-menu-open] .site-header__menu-toggle {
  background: var(--color-bg-subtle);
}

.site-header[data-menu-open] .site-header__menu-icon {
  background: transparent;
}

.site-header[data-menu-open] .site-header__menu-icon::before {
  top: 0;
  transform: translateX(-50%) rotate(45deg);
}

.site-header[data-menu-open] .site-header__menu-icon::after {
  top: 0;
  transform: translateX(-50%) rotate(-45deg);
}

.site-header__menu-toggle:focus-visible {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
}

/* ============================================
   Mobile menu panel
   ============================================ */

.mobile-menu {
  border-top: 1px solid var(--color-border);
  background: white;
  overflow: hidden;
  max-height: 0;
  opacity: 0;
  transition: max-height 0.3s ease, opacity 0.2s ease;
}

.mobile-menu[hidden] {
  display: none;
}

.site-header[data-menu-open] .mobile-menu {
  max-height: 600px;
  opacity: 1;
}

.mobile-menu__nav {
  display: flex;
  flex-direction: column;
  padding: var(--space-4) var(--space-6) var(--space-6);
  gap: var(--space-2);
}

.mobile-menu__nav a {
  display: block;
  padding: var(--space-3) 0;
  font-size: var(--fs-base);
  font-weight: 500;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border);
}

.mobile-menu__nav a:last-child {
  border-bottom: none;
  margin-top: var(--space-3);
}

.mobile-menu__nav a:hover {
  color: var(--color-primary);
}

/* ============================================
   Responsive: swap nav for hamburger on narrow viewports
   ============================================ */

@media (max-width: 900px) {
  .site-header__nav { display: none; }
  .site-header__donate { display: none; }
  .site-header__menu-toggle { display: block; }
}

/* Body lock when menu open (no horizontal scroll) */
body.menu-open {
  overflow: hidden;
}