/**
 * 顶部栏独立样式（与左侧栏 sidebar_v2_fixed.css 同级，由 _top_nav.html 按需引入）
 * 可单独加载；若已加载 variables.css 则使用其变量，否则使用各属性中的 fallback。
 */
/* ============================================
   顶部导航栏样式
   ============================================ */
.navbar {
  background: #000000;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.25), 0 0 0 1px rgba(255, 255, 255, 0.05) inset;
  position: fixed !important;
  top: 0 !important;
  left: 0 !important;
  right: 0 !important;
  z-index: 1030 !important;
  width: 100%;
  height: var(--navbar-height, 62px);
  min-height: var(--navbar-height, 62px);
  padding: var(--spacing-sm, 8px) 0;
  backdrop-filter: blur(10px);
  display: flex !important;
  flex-direction: row !important;
  align-items: center;
}

.navbar::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: transparent;
  pointer-events: none;
  opacity: 0;
}

.navbar-brand {
  color: #fff !important;
  font-weight: 700;
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm, 8px);
  padding: var(--spacing-xs, 4px) var(--spacing-md, 16px);
  margin-left: var(--spacing-md, 16px);
  border-radius: 0;
  position: relative;
  z-index: 1;
  font-size: var(--font-size-lg, 18px);
}

.navbar-brand i {
  font-size: 24px;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.navbar-nav {
  position: relative;
  z-index: 1;
  display: flex !important;
  flex-direction: row !important;
  flex-wrap: nowrap !important;
  align-items: center;
}

.nav-item {
  margin: 0 2px;
  position: relative;
  display: inline-block;
  white-space: nowrap;
}

.navbar .nav-link {
  color: rgba(255, 255, 255, 0.9) !important;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: var(--spacing-xs, 4px) var(--spacing-sm, 8px) !important;
  border-radius: 0;
  position: relative;
  font-weight: 500;
  font-size: var(--font-size-base, 14px);
  white-space: nowrap;
}

.navbar .nav-link::before {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.8), transparent);
  border-radius: 0;
}

.navbar .nav-link:hover::before {
  width: calc(100% - var(--spacing-md, 16px));
}

.navbar .nav-link.active {
  color: #fff !important;
  font-weight: 600;
  background: rgba(255, 255, 255, 0.15);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.navbar .nav-link.active::before {
  width: calc(100% - var(--spacing-md, 16px));
  background: linear-gradient(90deg, transparent, #fff, transparent);
  height: 3px;
}

/* 下拉菜单（顶部栏内） */
.dropdown-menu {
  background: #fff;
  border: 1px solid rgba(20, 47, 91, 0.15);
  border-radius: 0;
  box-shadow: var(--shadow-lg, 0 16px 32px rgba(0, 0, 0, 0.16));
  margin-top: var(--spacing-sm, 8px);
  padding: var(--spacing-sm, 8px) 0;
  min-width: 180px;
}

.dropdown-item {
  padding: var(--spacing-sm, 8px) var(--spacing-md, 16px);
  color: var(--vh-text, #000);
  font-size: var(--font-size-base, 14px);
  transition: background var(--transition-base, 0.2s ease);
}

.dropdown-item:hover,
.dropdown-item:focus {
  background: rgba(20, 47, 91, 0.08);
  color: var(--vh-primary, #1A1A1A);
}

.dropdown-divider {
  margin: var(--spacing-xs, 4px) 0;
  border-top: 1px solid var(--vh-border, #E0E0E0);
}

.dropdown-toggle::after {
  margin-left: var(--spacing-xs, 4px);
  vertical-align: 0.2em;
}

.navbar-nav .nav-item.dropdown {
  position: relative;
}

/* 布局 */
.navbar .container-fluid {
  display: flex !important;
  flex-direction: row !important;
  align-items: center;
  width: 100%;
  padding-left: 0 !important;
  padding-right: 0 !important;
  margin-left: 0 !important;
  margin-right: 0 !important;
}

.navbar-collapse {
  display: flex !important;
  flex-direction: row !important;
  flex-grow: 1;
  align-items: center;
  justify-content: space-between;
}

.navbar-nav {
  flex-direction: row !important;
  flex-wrap: nowrap !important;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.3) transparent;
}

.navbar-nav.me-auto {
  flex: 1;
  margin-right: var(--spacing-md, 16px);
}

.navbar-nav:not(.me-auto) {
  margin-left: auto;
  margin-right: var(--spacing-md, 16px);
  flex-shrink: 0;
}

.navbar-nav::-webkit-scrollbar {
  height: 4px;
}

.navbar-nav::-webkit-scrollbar-track {
  background: transparent;
}

.navbar-nav::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.3);
  border-radius: 0;
}

.navbar-nav::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.5);
}

@media (max-width: 991.98px) {
  .navbar-toggler {
    display: none !important;
  }
  .navbar-collapse {
    display: flex !important;
    flex-direction: row !important;
  }
}