/* ================================
   CSS CUSTOM PROPERTIES & VARIABLES
   ================================ */
   :root {
    --nav-transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --nav-border-radius: 6px;
    --nav-shadow: 0 4px 20px rgba(0,0,0,0.08);
    --nav-shadow-soft: 0 2px 10px rgba(0,0,0,0.1);
    --nav-z-index-overlay: 999;
    --nav-z-index-menu: 1000;
    --nav-z-index-toggle: 1001;
  }
  
  /* ================================
     BASE NAVIGATION STYLES
     ================================ */
  
  /* Level 1: Main Navigation */
  .main-nav-tabs {
    display: flex;
    justify-content: center;
    gap: 0;
    padding: 0;
    background: var(--white);
    position: relative;
  }
  
  .main-nav-tabs a {
    display: flex;
    align-items: center;
    text-decoration: none;
    padding: 5px 15px;
    font-weight: 500;
    font-size: 1rem;
    color: var(--text);
    border-bottom: 3px solid transparent;
    transition: var(--nav-transition);
    background: var(--white);
    white-space: nowrap;
  }
  
  .main-nav-tabs a:hover,
  .main-nav-tabs a:focus,
  .main-nav-tabs a.active {
    border-bottom-color: var(--accent);
  }
  
  /* Level 2: Secondary Navigation */
  .secondary-nav-box {
    background: linear-gradient(135deg, var(--secondary) 0%, #f0f2f5 100%);
    border-bottom: 1px solid var(--border);
    box-shadow: inset 0 1px 0 rgba(255,255,255,0.8);
    position: relative;
    overflow: visible;
  }
  
  .secondary-nav-box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--accent);
    opacity: 0.3;
  }
  
  .category-menu {
    display: none;
    opacity: 0;
    transform: translateY(-10px);
    transition: var(--nav-transition);
  }
  
  .category-menu.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
  }
  
  .secondary-nav {
    display: flex;
    list-style: none;
    gap: 0;
    margin: 0;
    padding: 0.8rem 0;
    flex-wrap: wrap;
  }
  
  .secondary-nav > li {
    position: relative;
    margin: 0;
  }
  
  .secondary-nav > li > a {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    font-size: 0.95rem;
    padding: 5px 10px;
    border-radius: var(--nav-border-radius);
    transition: var(--nav-transition);
    position: relative;
    white-space: nowrap;
    margin: 0 0.2rem;
  }
  
  .secondary-nav > li > a::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-accent);
    border-radius: var(--nav-border-radius);
    opacity: 0;
    transform: scale(0.9);
    transition: var(--nav-transition);
    z-index: -1;
  }
  
  .secondary-nav > li > a:hover,
  .secondary-nav > li > a:focus,
  .secondary-nav > li.active > a,
  .secondary-nav > li.menu-item-has-children:hover > a {
    color: var(--white);
    box-shadow: var(--nav-shadow-soft);
  }
  
  .secondary-nav > li > a:hover::before,
  .secondary-nav > li > a:focus::before,
  .secondary-nav > li.active > a::before,
  .secondary-nav > li.menu-item-has-children:hover > a::before {
    opacity: 1;
    transform: scale(1);
  }
  
  /* Level 3: Tertiary Navigation */
  .tertiary-nav-box {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--nav-shadow);
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 998;
    max-height: 60vh;
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: var(--nav-transition);
  }
  
  .tertiary-nav-box.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  
  /* Submenu Containers */
  .submenu-container {
    display: none;
    opacity: 0;
  }
  
  .submenu-container.active {
    display: block;
    opacity: 1;
  }
  
  /* Navbar Sections */
  .navbar-section {
    display: none;
    transition: var(--nav-transition);
    padding: 1rem 0;
    min-height: calc(60vh - 100px);
  }
  
  .navbar-content-section {
    transition: opacity 0.3s ease, transform 0.3s ease !important;
    transform: translateY(10px);
    border: 2px solid transparent;
  }
  
  .navbar-content-section[style*="opacity: 1"] {
    transform: translateY(0) !important;
  }
  
  .navbar-content-section[style*="display: none"] {
    opacity: 0 !important;
    visibility: hidden !important;
  }
  
  .navbar-content-section[style*="display: block"] {
    visibility: visible !important;
  }
  
  .navbar-section[style*="display: block"] {
    opacity: 1 !important;
    visibility: visible !important;
  }
  
  .navbar-section-container {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 3rem;
    align-items: start;
  }
  
  /* Left Navigation */
  .navbar-section-left {
    list-style: none;
    margin: 0;
    padding: 0;
  }
  
  .navbar-list-item {
    margin-bottom: 0.5rem;
  }
  
  .navbar-list-item:last-child {
    margin-bottom: 0;
  }
  
  .navbar-list-link {
    display: block;
    text-decoration: none;
    padding: 5px 10px;
  }
  
  .navbar-text {
    margin: 0;
    color: var(--text);
    font-weight: 500;
    font-size: 0.9rem;
    transition: var(--nav-transition);
    position: relative;
    z-index: 1;
  }
  
  .navbar-list-link:hover .navbar-text {
    color: var(--accent);
  }
  
  /* Right Content Area */
  .navbar-section-content {
    background: var(--white);
  }
  
  .navbar-content-title {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary);
    margin: 0 0 1.2rem 0;
    padding-bottom: 0.8rem;
    border-bottom: 2px solid transparent;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    position: relative;
  }
  
  .navbar-content-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient-accent);
    opacity: 0.3;
  }
  
  .navbar-content-section-menus {
    display: flex;
    flex-direction: row;
    gap: 5px;
    flex-wrap: wrap;
  }
  
  .menu-item-link {
    text-decoration: none;
    color: var(--text-light);
    font-size: 0.9rem;
    padding: 0;
    width: calc(100% / 3 - 30px);
  }
  
  .menu-item-link:hover .menu-item-name {
    color: var(--primary);
    border-bottom: 1px solid var(--accent);
  }
  
  /* ================================
     MOBILE HAMBURGER MENU
     ================================ */
  
  /* Mobile Menu Toggle */
  .mobile-menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 44px;
    height: 44px;
    background: transparent;
    border: none;
    cursor: pointer;
    z-index: var(--nav-z-index-toggle);
    position: relative;
    padding: 8px;
  }
  
  .mobile-menu-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--text);
    margin: 3px 0;
    transition: var(--nav-transition);
    border-radius: 2px;
  }
  
  .mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
  }
  
  .mobile-menu-toggle.active span:nth-child(2) {
    opacity: 0;
  }
  
  .mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
  }
  
  /* Mobile Menu Overlay & Container */
  .mobile-menu-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: var(--nav-z-index-overlay);
    opacity: 0;
    visibility: hidden;
    transition: var(--nav-transition);
    overscroll-behavior: none;
  }
  
  .mobile-menu-overlay.active {
    opacity: 1;
    visibility: visible;
  }
  
  .mobile-menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 85%;
    max-width: 400px;
    height: 100vh;
    height: 100dvh;
    background: var(--white);
    z-index: var(--nav-z-index-menu);
    transition: right 0.3s ease;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    box-shadow: -5px 0 15px rgba(0,0,0,0.1);
    overscroll-behavior: contain;
  }
  
  .mobile-menu.active {
    right: 0;
  }
  
  /* Prevent background scroll */
  body.mobile-menu-open,
  html.mobile-menu-open {
    overflow: hidden !important;
  }
  
  body.mobile-menu-open {
    position: fixed !important;
    width: 100% !important;
    height: 100% !important;
  }
  
  /* Mobile Menu Header */
  .mobile-menu-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    background: var(--secondary);
    position: sticky;
    top: 0;
    z-index: 1;
  }
  
  .mobile-menu-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary);
  }
  
  .mobile-menu-close {
    background: transparent;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px;
    color: var(--text);
    min-width: 30px;
    min-height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  /* Mobile Menu Content */
  .mobile-menu-content {
    padding: 0 0 env(safe-area-inset-bottom, 20px) 0;
  }
  
  .mobile-category-item {
    border-bottom: 1px solid var(--border);
  }
  
  .mobile-category-header,
  .mobile-secondary-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: var(--white);
    cursor: pointer;
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    transition: background-color 0.3s ease;
    min-height: 48px;
    -webkit-tap-highlight-color: transparent;
  }
  
  .mobile-secondary-header {
    padding: 0.8rem 1.5rem;
    font-size: 0.9rem;
    min-height: 44px;
  }
  
  .mobile-category-header:hover,
  .mobile-category-header:active,
  .mobile-secondary-header:hover,
  .mobile-secondary-header:active {
    background: var(--secondary);
  }
  
  .mobile-secondary-header:hover,
  .mobile-secondary-header:active {
    background: rgba(255,255,255,0.5);
  }
  
  .mobile-category-arrow {
    transition: transform 0.3s ease;
    font-size: 0.8rem;
    color: var(--text-light);
  }
  
  .mobile-category-item.active .mobile-category-arrow {
    transform: rotate(180deg);
  }
  
  /* Mobile Secondary & Tertiary Menus */
  .mobile-secondary-menu,
  .mobile-tertiary-menu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }
  
  .mobile-secondary-menu {
    background: var(--secondary);
  }
  
  .mobile-category-item.active .mobile-secondary-menu {
    max-height: 500px;
  }
  
  .mobile-tertiary-menu {
    background: rgba(255,255,255,0.3);
  }
  
  .mobile-secondary-item.active .mobile-tertiary-menu {
    max-height: 400px;
  }
  
  .mobile-secondary-item {
    border-bottom: 1px solid rgba(224,224,224,0.3);
  }
  
  .mobile-secondary-item:last-child {
    border-bottom: none;
  }
  
  .mobile-tertiary-section {
    padding: 0.5rem 2rem;
  }
  
  .mobile-tertiary-title {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 0.5rem;
    padding-bottom: 0.3rem;
    border-bottom: 1px solid rgba(0,124,186,0.2);
  }
  
  .mobile-tertiary-links {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
  }
  
  .mobile-tertiary-links a {
    text-decoration: none;
    color: var(--text-light);
    font-size: 0.8rem;
    padding: 0.3rem 0;
    transition: color 0.3s ease;
    min-height: 36px;
    display: flex;
    align-items: center;
    -webkit-tap-highlight-color: transparent;
  }
  
  .mobile-tertiary-links a:hover,
  .mobile-tertiary-links a:active {
    color: var(--accent);
  }
  
  /* ================================
     RESPONSIVE DESIGN
     ================================ */
  
  /* Tablet and below */
  @media (max-width: 768px) {
    .mobile-menu-toggle {
      display: flex !important;
    }
  
    .desktop-navigation,
    .main-nav-tabs,
    .secondary-nav-box,
    .tertiary-nav-box {
      display: none !important;
    }
  
    .site-branding {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 0.5rem 0;
    }
  
    .site-identity {
      flex: 1;
      text-align: center;
    }
  
    .site-title {
      font-size: 1.2rem !important;
      margin: 0;
    }
  
    .site-description {
      display: none;
    }
  
    .navbar-section-container {
      grid-template-columns: 1fr;
      gap: 1.5rem;
    }
  
    .navbar-section-left {
      order: 2;
      padding: 1rem;
    }
  
    .navbar-section-content {
      order: 1;
    }
  
    .navbar-content-section {
      padding: 1rem;
    }
  
    .tertiary-nav-box {
      max-height: 60vh;
      position: absolute;
    }
  }
  
  /* Desktop and above */
  @media (min-width: 769px) {
    .mobile-menu-toggle,
    .mobile-menu,
    .mobile-menu-overlay {
      display: none !important;
    }
  
    .desktop-navigation {
      display: block !important;
    }
  }
  
  /* Small mobile devices */
  @media (max-width: 480px) {
    .mobile-menu {
      width: 90%;
      max-width: 320px;
    }
  
    .mobile-menu-header {
      padding: 0.8rem;
    }
  
    .mobile-category-header,
    .mobile-secondary-header {
      padding: 0.8rem;
      font-size: 0.9rem;
    }
  
    .site-title {
      font-size: 1rem !important;
    }
  
    .navbar-section {
      padding: 1rem 0;
    }
  
    .navbar-content-section {
      padding: 1rem;
    }
  
    .navbar-content-title {
      font-size: 1rem;
    }
  }
  
  /* Landscape mobile */
  @media (max-width: 768px) and (orientation: landscape) {
    .mobile-menu {
      height: 100vh;
      height: 100dvh;
    }
  
    .mobile-menu-header {
      padding: 0.5rem 1rem;
    }
  
    .mobile-category-header,
    .mobile-secondary-header {
      padding: 0.6rem 1rem;
    }
  }
  
  /* ================================
     ACCESSIBILITY & PERFORMANCE
     ================================ */
  
  /* iOS Safari fixes */
  @supports (-webkit-appearance: none) {
    .mobile-menu,
    .mobile-menu-overlay {
      height: -webkit-fill-available;
    }
  }
  
  /* Safe area support for notched devices */
  @supports (padding: max(0px)) {
    .mobile-menu-content {
      padding-left: max(1rem, env(safe-area-inset-left));
      padding-right: max(1rem, env(safe-area-inset-right));
      padding-bottom: max(1rem, env(safe-area-inset-bottom));
    }
  
    .mobile-menu-header {
      padding-left: max(1rem, env(safe-area-inset-left));
      padding-right: max(1rem, env(safe-area-inset-right));
      padding-top: max(1rem, env(safe-area-inset-top));
    }
  }
  
  /* Reduced motion support */
  @media (prefers-reduced-motion: reduce) {
    .main-nav-tabs a,
    .secondary-nav > li > a,
    .navbar-list-link,
    .menu-item-link,
    .category-menu,
    .submenu-container,
    .navbar-section,
    .mobile-menu-toggle span,
    .mobile-menu,
    .mobile-menu-overlay {
      transition: none !important;
      transform: none !important;
    }
  }
  
  /* High contrast mode */
  @media (prefers-contrast: high) {
    .main-nav-tabs a,
    .secondary-nav > li > a {
      border: 2px solid currentColor;
    }
  
    .navbar-content-section {
      border: 2px solid var(--primary);
    }
  }
  
  /* Print styles */
  @media print {
    .secondary-nav-box,
    .tertiary-nav-box,
    .mobile-menu-toggle,
    .mobile-menu,
    .mobile-menu-overlay {
      display: none !important;
    }
  }