/* ============================================================
   导航栏样式 - 固定导航栏 + 二级下拉菜单
   ============================================================ */

/* 导航栏容器 */
.navbar {
  position: sticky;
  top: 0;
  background: rgba(250, 250, 250, 0.9);
  box-shadow: 0 12px 32px rgba(12, 36, 73, 0.12);
  z-index: var(--z-index-sticky);
  transition: all var(--transition-fast);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(12, 63, 125, 0.08);
  color: var(--color-dark-text);
}

.navbar.scrolled {
  background: rgba(4, 24, 56, 0.92);
  box-shadow: 0 18px 40px rgba(4, 24, 56, 0.35);
  color: rgba(255, 255, 255, 0.92);
}

.navbar.scrolled .navbar-logo,
.navbar.scrolled .navbar-link {
  color: rgba(255, 255, 255, 0.9);
}

.navbar.scrolled .navbar-link:hover {
  color: var(--color-secondary);
  background: rgba(255, 152, 0, 0.12);
}

.navbar.scrolled .navbar-link::after {
  background-color: var(--color-secondary);
}

.navbar-container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

/* Logo样式 */
.navbar-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  text-decoration: none;
  color: var(--color-primary);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  transition: color var(--transition-fast);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.navbar-logo:hover {
  color: var(--color-secondary);
}

/* 导航菜单 */
.navbar-menu {
  display: flex;
  flex-wrap: nowrap;
  list-style: none;
  gap: 0;
  margin: 0;
  padding: 0;
}

.navbar-item {
  position: relative;
}

.navbar-link {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: inherit;
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
  position: relative;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.navbar-link:hover {
  color: var(--color-primary);
  background: rgba(77, 208, 225, 0.08);
}

/* 导航链接下划线效果 */
.navbar-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-primary);
  transition: width var(--transition-fast);
}

.navbar-link:hover::after {
  width: 100%;
}

/* 二级下拉菜单 */
.navbar-dropdown {
  position: absolute;
  top: 100%;
  left: 0;
  background-color: var(--color-white);
  min-width: 200px;
  list-style: none;
  margin: 0;
  padding: var(--spacing-sm) 0;
  border-radius: var(--border-radius-base);
  box-shadow: 0 18px 40px rgba(5, 31, 71, 0.18);
  border: 1px solid rgba(0, 92, 175, 0.08);
  backdrop-filter: blur(16px);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-fast);
  z-index: var(--z-index-dropdown);
}

.navbar-item:hover .navbar-dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.navbar-dropdown-item {
  display: block;
  padding: var(--spacing-sm) var(--spacing-lg);
  color: var(--color-dark-text);
  text-decoration: none;
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}

.navbar-dropdown-item:hover {
  background-color: rgba(0, 92, 175, 0.08);
  color: var(--color-primary);
  border-left-color: var(--color-secondary);
  padding-left: calc(var(--spacing-lg) + 4px);
}

/* 下拉菜单指示器 */
.navbar-link.has-dropdown::after {
  content: '▾';
  position: static;
  display: inline-block;
  margin-left: var(--spacing-sm);
  font-size: 0.6em;
  width: auto;
  height: auto;
  background: none;
  transition: transform var(--transition-fast);
}

.navbar-item:hover .navbar-link.has-dropdown::after {
  transform: rotate(180deg);
}

/* 移动菜单按钮 */
.navbar-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
  color: var(--color-dark-text);
  font-size: var(--font-size-2xl);
}

/* 响应式设计 */
@media (max-width: 768px) {
  .navbar-container {
    height: 60px;
  }

  .navbar-menu {
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--color-white);
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-fast);
    box-shadow: var(--box-shadow-md);
    gap: 0;
  }

  .navbar-menu.active {
    max-height: 500px;
  }

  .navbar-item {
    width: 100%;
    border-bottom: 1px solid var(--color-border-light);
  }

  .navbar-link {
    padding: var(--spacing-base) var(--spacing-lg);
  }

  .navbar-link::after {
    display: none;
  }

  .navbar-dropdown {
    position: static;
    opacity: 0;
    visibility: hidden;
    max-height: 0;
    overflow: hidden;
    transform: none;
    box-shadow: none;
    background-color: var(--color-light);
    border-radius: 0;
    transition: all var(--transition-fast);
  }

  .navbar-item:hover .navbar-dropdown {
    opacity: 0;
    visibility: hidden;
  }

  .navbar-dropdown.active {
    opacity: 1;
    visibility: visible;
    max-height: 300px;
  }

  .navbar-dropdown-item {
    padding-left: var(--spacing-2xl);
  }

  .navbar-dropdown-item:hover {
    padding-left: calc(var(--spacing-2xl) + 4px);
  }

  .navbar-toggle {
    display: block;
  }

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

}

@media (max-width: 480px) {
  .navbar-container {
    height: 55px;
  }

  .navbar-menu.active {
    max-height: 400px;
  }

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

  .navbar-link {
    padding: var(--spacing-sm) var(--spacing-base);
    font-size: var(--font-size-sm);
  }
}

/* 导航栏右侧按钮组 */
.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-base);
}

.navbar-action-btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  background: linear-gradient(135deg, var(--color-secondary), var(--color-primary));
  color: var(--color-white);
  border: none;
  border-radius: var(--border-radius-base);
  cursor: pointer;
  font-weight: var(--font-weight-medium);
  transition: all var(--transition-fast);
  font-size: var(--font-size-sm);
  box-shadow: 0 10px 28px rgba(255, 152, 0, 0.25);
}

.navbar-action-btn:hover {
  background: linear-gradient(135deg, var(--color-primary-dark), #002D5E);
  transform: translateY(-2px);
  box-shadow: 0 16px 32px rgba(4, 24, 56, 0.35);
}

@media (max-width: 768px) {
  .navbar-actions {
    gap: var(--spacing-sm);
  }

  .navbar-action-btn {
    padding: var(--spacing-sm) var(--spacing-base);
    font-size: var(--font-size-xs);
  }
}