/* ================================
   NAVIGATION - CLEAN & SCIENTIFIC
   Professional, accessible navigation
   ================================ */

/* ========== Main Navbar ========== */
.navbar {
  background: var(--white) !important;
  border-bottom: 1px solid var(--gray-200);
  padding: var(--space-4) var(--space-8) !important;
  min-height: 70px !important;
  transition: all var(--transition-base);
  box-shadow: none;
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.98) !important;
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  padding: var(--space-3) var(--space-8) !important;
  min-height: 65px !important;
  border-bottom-color: var(--gray-200);
}

.bg-dark {
  background-color: var(--white) !important;
  transition: all var(--transition-base);
}

/* ========== Brand Logo ========== */
.navbar-brand {
  color: var(--gray-900) !important;
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0;
  transition: all var(--transition-base);
}

.navbar-brand:hover {
  color: var(--primary) !important;
}

.navbar-brand img {
  width: 50px;
  height: 50px;
  border-radius: var(--radius-base);
  object-fit: cover;
  transition: all var(--transition-base);
  border: 2px solid var(--gray-200);
}

.navbar-brand:hover img {
  transform: scale(1.05);
  border-color: var(--primary);
}

/* ========== Navigation Links ========== */
.navbar-nav {
  margin: 0 auto;
  padding: 0;
  align-items: center;
  gap: var(--space-2);
}

.navbar-nav .nav-item {
  margin: 0;
}

.nav-link {
  color: var(--gray-700) !important;
  font-weight: var(--font-medium);
  font-size: var(--text-base) !important;
  padding: var(--space-3) var(--space-4) !important;
  border-radius: var(--radius-base);
  transition: all var(--transition-base);
  text-decoration: none;
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.nav-link:hover {
  color: var(--primary) !important;
  background: rgba(16, 185, 129, 0.1) !important;
}

.nav-link.active {
  color: var(--primary) !important;
  background: rgba(16, 185, 129, 0.15) !important;
  font-weight: var(--font-semibold);
}

/* ========== Dropdown Menu ========== */
.nav-item.dropdown {
  position: relative !important;
}

.nav-link.dropdown-toggle::after {
  content: '';
  display: inline-block;
  margin-left: var(--space-2);
  vertical-align: middle;
  border-top: 5px solid currentColor;
  border-right: 4px solid transparent;
  border-left: 4px solid transparent;
  transition: transform var(--transition-base);
}

.nav-item.dropdown:hover .dropdown-toggle::after,
.nav-item.dropdown.show .dropdown-toggle::after {
  transform: rotate(180deg);
}

.dropdown-menu {
  display: block;
  position: absolute;
  left: 50%;
  transform: translateX(-50%) translateY(10px);
  min-width: 320px;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-6);
  margin-top: var(--space-2);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
  z-index: var(--z-dropdown);
}

/* Show dropdown on hover for desktop */
@media (min-width: 992px) {
  .nav-item.dropdown:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
  }
}

/* Keep Bootstrap click behavior on all devices */
.nav-item.dropdown .dropdown-menu.show {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.dropdown-header {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--gray-900);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 0 0 var(--space-3) 0;
  margin-bottom: var(--space-3);
  border-bottom: 2px solid var(--gray-200);
}

.dropdown-item {
  padding: var(--space-3) var(--space-4);
  color: var(--gray-700);
  font-weight: var(--font-medium);
  font-size: var(--text-base);
  border-radius: var(--radius-base);
  transition: all var(--transition-base);
  text-decoration: none;
  display: block;
  white-space: nowrap;
}

.dropdown-item:hover {
  color: var(--primary);
  background: rgba(16, 185, 129, 0.1);
  padding-left: calc(var(--space-4) + var(--space-2));
}

.dropdown-menu .container {
  width: auto !important;
  max-width: none !important;
  padding: 0 !important;
}

.dropdown-menu .row {
  display: flex;
  gap: var(--space-8);
  margin: 0 !important;
}

.dropdown-menu .col-md-4 {
  flex: 1;
  min-width: 150px;
}

/* ========== Mobile Navigation ========== */
.navbar-toggler {
  border: 2px solid var(--gray-300);
  border-radius: var(--radius-base);
  padding: var(--space-3);
  transition: all var(--transition-base);
  color: var(--gray-700);
  position: relative;
}

.navbar-toggler:hover {
  background: var(--gray-100);
  border-color: var(--primary);
}

.navbar-toggler:focus {
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.25);
}

/* Custom hamburger icon for light navbar */
.navbar-toggler-icon {
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%2875, 85, 99, 1%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2.5' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
  width: 24px;
  height: 24px;
  display: inline-block;
}

.navbar-toggler:hover .navbar-toggler-icon {
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%2816, 185, 129, 1%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2.5' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

/* Small Mobile (320px - 575px) */
@media (max-width: 575px) {
  .navbar {
    padding: 0.4rem 0.6rem !important;
    min-height: 50px !important;
  }

  .navbar.scrolled {
    padding: 0.3rem 0.6rem !important;
    min-height: 48px !important;
  }

  .container-fluid {
    padding: 0 !important;
  }

  .navbar-brand {
    font-size: 0.875rem;
    gap: 0.4rem;
    padding: 0;
  }

  .navbar-brand img,
  .navbar img {
    width: 36px !important;
    height: 36px !important;
    border-radius: 4px;
  }

  .navbar-toggler {
    padding: 0.3rem 0.4rem;
    font-size: 0.9rem;
    border-width: 1px;
  }

  .navbar-toggler-icon {
    width: 18px;
    height: 18px;
  }

  /* Compact mobile menu */
  .navbar-collapse {
    background: var(--white);
    margin: 0.5rem -0.6rem 0;
    padding: 0;
    border-top: 1px solid var(--gray-200);
    max-height: calc(100vh - 55px);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
  }

  .navbar-nav {
    padding: 0;
    gap: 0;
    align-items: stretch;
  }

  .navbar-nav .nav-item {
    width: 100%;
    margin: 0;
  }

  .nav-link {
    width: 100%;
    padding: 0.55rem 0.85rem !important;
    font-size: 0.9rem !important;
    border-radius: 0 !important;
    border-bottom: 1px solid #f1f1f1;
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .nav-link:hover,
  .nav-link.active {
    background: #f8f9fa !important;
    color: var(--primary) !important;
  }

  .nav-item.dropdown {
    position: relative !important;
  }

  /* Compact dropdown menu */
  .dropdown-menu {
    position: static !important;
    width: 100% !important;
    transform: none !important;
    box-shadow: none !important;
    border: none !important;
    border-radius: 0 !important;
    margin: 0 !important;
    padding: 0 !important;
    background: #fafafa !important;
    float: none !important;
  }

  .dropdown-menu .container {
    max-width: 100% !important;
    margin: 0 !important;
    padding: 0 !important;
  }

  .dropdown-menu .row {
    margin: 0 !important;
    padding: 0 !important;
    flex-direction: column;
    gap: 0;
  }

  .dropdown-menu .col-md-4 {
    width: 100% !important;
    max-width: 100% !important;
    padding: 0 !important;
    margin: 0 !important;
  }

  .dropdown-item {
    padding: 0.5rem 0.85rem 0.5rem 1.5rem !important;
    font-size: 0.85rem !important;
    border-radius: 0 !important;
    border-bottom: 1px solid #f1f1f1;
    background: #fafafa !important;
    white-space: normal !important;
  }

  .dropdown-item:last-child {
    border-bottom: none;
  }

  .dropdown-item:hover,
  .dropdown-item:active {
    padding-left: 1.75rem !important;
    background: #f0f0f0 !important;
    color: var(--primary) !important;
  }

  /* Dropdown toggle arrow */
  .nav-link.dropdown-toggle {
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  .nav-link.dropdown-toggle::after {
    margin-left: auto;
    border-top-width: 5px;
    border-right-width: 5px;
    border-left-width: 5px;
    transition: transform 0.2s;
  }

  .nav-item.dropdown.show .nav-link.dropdown-toggle::after {
    transform: rotate(180deg);
  }

  /* Show dropdown state */
  .nav-item.dropdown.show .nav-link {
    background: #f0f0f0 !important;
  }

  /* Hide dropdown initially */
  .dropdown-menu:not(.show) {
    display: none !important;
  }

  .dropdown-menu.show {
    display: block !important;
  }
}

/* Medium Mobile (576px - 767px) */
@media (min-width: 576px) and (max-width: 767px) {
  .navbar {
    padding: var(--space-3) var(--space-4) !important;
    min-height: 64px !important;
  }

  .navbar-brand {
    font-size: var(--text-lg);
  }

  .navbar-brand img {
    width: 40px;
    height: 40px;
  }

  .navbar-nav {
    padding-top: var(--space-5);
    gap: var(--space-2);
  }

  .navbar-nav .nav-item {
    width: 100%;
  }

  .nav-link {
    width: 100%;
    padding: var(--space-3) var(--space-4) !important;
    font-size: var(--text-base) !important;
  }

  .dropdown-menu {
    position: static;
    width: 100%;
    transform: none;
    box-shadow: none;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-base);
    margin-top: var(--space-2);
    padding: var(--space-4);
  }

  .dropdown-menu .row {
    flex-direction: column;
    gap: var(--space-4);
  }

  .dropdown-menu .col-md-4 {
    width: 100%;
  }

  .navbar-collapse {
    background: var(--white);
    margin: var(--space-4) calc(-1 * var(--space-4));
    padding: var(--space-4);
    border-top: 1px solid var(--gray-200);
  }
}

/* Tablets (768px - 991px) */
@media (min-width: 768px) and (max-width: 991px) {
  .navbar {
    padding: var(--space-3) var(--space-5) !important;
  }

  .navbar-brand {
    font-size: var(--text-xl);
  }

  .navbar-brand img {
    width: 44px;
    height: 44px;
  }

  .navbar-nav {
    padding-top: var(--space-6);
    gap: var(--space-2);
  }

  .navbar-nav .nav-item {
    width: 100%;
  }

  .nav-link {
    width: 100%;
    padding: var(--space-4) !important;
    font-size: var(--text-lg) !important;
  }

  .nav-item.dropdown {
    position: relative !important;
  }

  .dropdown-menu {
    position: static;
    width: 100%;
    transform: none;
    box-shadow: none;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-base);
    margin-top: var(--space-2);
    padding: var(--space-5);
  }

  .dropdown-menu .row {
    flex-direction: column;
    gap: var(--space-6);
  }

  .dropdown-menu .col-md-4 {
    width: 100%;
  }

  .navbar-collapse {
    background: var(--white);
    margin: var(--space-4) calc(-1 * var(--space-5));
    padding: var(--space-4) var(--space-5);
    border-top: 1px solid var(--gray-200);
  }
}

/* Small Laptops (992px - 1199px) */
@media (min-width: 992px) and (max-width: 1199px) {
  .navbar-nav {
    gap: var(--space-1);
  }

  .nav-link {
    padding: var(--space-2) var(--space-3) !important;
    font-size: var(--text-sm) !important;
  }

  .dropdown-menu {
    min-width: 280px;
  }
}

/* ========== Accessibility ========== */
.navbar-nav .nav-link:focus,
.dropdown-item:focus,
.navbar-toggler:focus {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

/* ========== Skip to content link (a11y) ========== */
.skip-to-content {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary);
  color: var(--white);
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-base);
  font-weight: var(--font-semibold);
  text-decoration: none;
  z-index: var(--z-tooltip);
  transition: all var(--transition-base);
}

.skip-to-content:focus {
  top: var(--space-4);
}