/**
 * NAVIGATION STYLES
 * 
 * Styles for the site header and navigation, including mobile menu.
 * Features sticky header and responsive hamburger menu.
 */

/* ===== HEADER ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-primary);
  z-index: var(--z-sticky);
  /* Smooth backdrop blur for modern look */
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: 0 var(--space-md);
}

/* ===== LOGO ===== */
.site-logo {
  font-family: var(--font-headings);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-logo:hover {
  color: var(--accent-soft);
  text-decoration: none;
}

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

/* ===== NAVIGATION ===== */
.main-nav {
  display: none; /* Hidden on mobile, shown on desktop */
}

.nav-list {
  display: flex;
  gap: var(--space-xl);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-base);
  text-decoration: none;
  padding: var(--space-sm) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-primary);
  text-decoration: none;
}

/* Active page indicator - underline */
.nav-link.active {
  color: var(--accent-soft);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--accent-primary);
}

/* ===== SOCIAL LINKS (Desktop) ===== */
.header-social {
  display: none; /* Hidden on mobile */
}

.social-list {
  display: flex;
  gap: var(--space-md);
  list-style: none;
  margin: 0;
  padding: 0;
}

.social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  border-radius: var(--radius-sm);
}

.social-link:hover {
  color: var(--accent-soft);
}

.social-link svg {
  width: 20px;
  height: 20px;
}

/* ===== MOBILE MENU BUTTON ===== */
.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  color: var(--text-primary);
  background: none;
  border: none;
  cursor: pointer;
  z-index: var(--z-overlay);
  transition: color var(--transition-fast);
}

.mobile-menu-toggle:hover {
  color: var(--accent-soft);
}

.mobile-menu-toggle:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Hamburger icon */
.hamburger {
  position: relative;
  width: 24px;
  height: 18px;
}

.hamburger span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: currentColor;
  transition: all var(--transition-base);
}

.hamburger span:nth-child(1) {
  top: 0;
}

.hamburger span:nth-child(2) {
  top: 8px;
}

.hamburger span:nth-child(3) {
  top: 16px;
}

/* Hamburger animation when menu is open */
.mobile-menu-toggle.active .hamburger span:nth-child(1) {
  top: 8px;
  transform: rotate(45deg);
}

.mobile-menu-toggle.active .hamburger span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle.active .hamburger span:nth-child(3) {
  top: 8px;
  transform: rotate(-45deg);
}

/* ===== MOBILE MENU OVERLAY ===== */
.mobile-menu {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-primary);
  z-index: var(--z-modal);
  /* Hidden by default */
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
  /* Prevent scrolling when menu is open */
  overflow-y: auto;
  padding-top: var(--header-height);
}

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

.mobile-nav {
  padding: var(--space-2xl) var(--space-md);
}

.mobile-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.mobile-nav-link {
  display: block;
  padding: var(--space-md);
  color: var(--text-secondary);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.mobile-nav-link:hover {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  text-decoration: none;
}

.mobile-nav-link.active {
  background-color: var(--bg-secondary);
  color: var(--accent-soft);
  border-left: 4px solid var(--accent-primary);
}

/* Mobile social links */
.mobile-social {
  padding: var(--space-xl) var(--space-md);
  border-top: 1px solid var(--border-primary);
  margin-top: var(--space-xl);
}

.mobile-social-title {
  color: var(--text-muted);
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-md);
}

.mobile-social-list {
  display: flex;
  gap: var(--space-md);
  list-style: none;
  margin: 0;
  padding: 0;
}

.mobile-social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: var(--bg-secondary);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

.mobile-social-link:hover {
  background-color: var(--bg-tertiary);
  color: var(--accent-soft);
}

.mobile-social-link svg {
  width: 24px;
  height: 24px;
}

/* ===== DESKTOP NAVIGATION (768px+) ===== */
@media (min-width: 768px) {
  .header-container {
    padding: 0 var(--space-xl);
  }
  
  .main-nav {
    display: block;
  }
  
  .header-social {
    display: block;
  }
  
  .mobile-menu-toggle {
    display: none;
  }
  
  .mobile-menu {
    display: none;
  }
}

/* ===== LARGE DESKTOP (1024px+) ===== */
@media (min-width: 1024px) {
  .header-container {
    padding: 0 var(--space-2xl);
  }
  
  .nav-list {
    gap: var(--space-2xl);
  }
}