/* ============================================
 * Navigation - Header, Nav Links, Mobile Menu
 * All values reference CSS variables from variables.css
 * ============================================ */

/* --- Header --- */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-sticky);
  padding: var(--space-2) 0 var(--space-4);
  background-color: transparent;
  transition: background-color var(--duration-base) var(--easing-ease),
    box-shadow var(--duration-base) var(--easing-ease),
    padding var(--duration-base) var(--easing-ease);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

/* Scrolled state - solid background with shadow */
.header--scrolled {
  background-color: var(--color-background);
  box-shadow: var(--shadow-md);
  padding: var(--space-2) 0;
}

/* Body offset for fixed header */
body {
  padding-top: 72px;
}

/* --- Logo --- */

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

.site-logo__icon {
  display: block;
  width: 48px;
  height: auto;
  flex-shrink: 0;
}

@media (min-width: 768px) {
  .site-logo__icon {
    width: 64px;
  }
}

.site-logo__text {
  font-family: var(--font-heading);
  font-size: var(--font-size-h3);
  color: var(--color-text);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
}

.site-logo:hover .site-logo__text {
  color: var(--color-primary-dark);
}

.site-logo:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

/* --- Desktop Nav Links --- */

.nav-links {
  display: none;
  align-items: center;
  gap: var(--space-8);
}

.nav-link {
  position: relative;
  font-family: var(--font-body);
  font-size: var(--font-size-body);
  font-weight: var(--weight-medium);
  color: var(--color-text);
  text-decoration: none;
  padding: var(--space-2) 0;
  transition: color var(--duration-fast) var(--easing-ease);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 1px;
  background-color: var(--color-primary-dark);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 200ms var(--easing-out);
}

.nav-link:hover {
  color: var(--color-primary-dark);
}

.nav-link:hover::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--color-primary-dark);
}

.nav-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

/* --- Header Actions (Cart) --- */

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

/* --- Cart Button --- */

.cart-toggle {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  color: var(--color-text);
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: color var(--duration-fast) var(--easing-ease);
}

.cart-toggle:hover {
  color: var(--color-primary-dark);
}

.cart-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.cart-toggle svg {
  width: 24px;
  height: 24px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* Cart badge */
.cart-badge {
  position: absolute;
  top: 4px;
  right: 2px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  padding: 0 var(--space-1);
  font-family: var(--font-body);
  font-size: var(--font-size-xs);
  font-weight: var(--weight-semibold);
  line-height: 1;
  color: var(--color-surface);
  background-color: var(--color-primary-dark);
  border-radius: var(--radius-full);
}

.cart-badge:empty,
.cart-badge[data-count="0"] {
  display: none;
}

/* --- Hamburger Button --- */

.menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text);
  border-radius: var(--radius-md);
  transition: color var(--duration-fast) var(--easing-ease);
}

.menu-toggle:hover {
  color: var(--color-primary-dark);
}

.menu-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.menu-toggle__icon {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 22px;
  height: 22px;
}

.menu-toggle__icon span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: currentColor;
  border-radius: 1px;
  transition: transform var(--duration-base) var(--easing-out),
    opacity var(--duration-fast) var(--easing-ease);
}

/* Hamburger to X transform */
.menu-toggle[aria-expanded="true"] .menu-toggle__icon span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__icon span:nth-child(2) {
  opacity: 0;
}

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

/* --- Mobile Menu Overlay --- */

.mobile-menu {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: var(--z-overlay);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-8);
  background-color: var(--color-background);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--duration-base) var(--easing-out),
    visibility var(--duration-base) var(--easing-out);
}

.mobile-menu.is-open {
  opacity: 1;
  visibility: visible;
}

.mobile-menu__link {
  font-family: var(--font-heading);
  font-size: var(--font-size-h2);
  color: var(--color-text);
  text-decoration: none;
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-tight);
  transition: color var(--duration-fast) var(--easing-ease);
}

.mobile-menu__link:hover,
.mobile-menu__link:focus {
  color: var(--color-primary-dark);
}

.mobile-menu__link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}

.mobile-menu__link[aria-current="page"] {
  color: var(--color-primary-dark);
}

/* --- Close Button (inside mobile menu) --- */

.mobile-menu__close {
  position: absolute;
  top: var(--space-4);
  right: var(--space-6);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--color-text);
  border-radius: var(--radius-md);
  transition: color var(--duration-fast) var(--easing-ease);
}

.mobile-menu__close:hover {
  color: var(--color-primary-dark);
}

.mobile-menu__close:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.mobile-menu__close svg {
  width: 24px;
  height: 24px;
  stroke: currentColor;
  stroke-width: 2;
}

/* --- Desktop Breakpoint (768px+) --- */

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

  .menu-toggle {
    display: none;
  }

  .mobile-menu {
    display: none;
  }

  body {
    padding-top: 80px;
  }
}

/* --- Reduced Motion --- */

@media (prefers-reduced-motion: reduce) {
  .site-header {
    transition: none;
  }

  .mobile-menu {
    transition: none;
  }

  .nav-link::after {
    transition: none;
  }

  .menu-toggle__icon span {
    transition: none;
  }
}