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

/* 导航栏容器 */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--box-shadow-base);
  -webkit-backdrop-filter: blur(18px);
  backdrop-filter: blur(18px);
  padding: 0;
}

.navbar-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  height: 70px;
}

/* Logo 样式 */
.navbar-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  text-decoration: none;
  font-size: var(--font-size-h4);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  transition: var(--transition-fast);
}

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

.navbar-logo img {
  height: 50px;
  width: auto;
}

/* 导航菜单 */
.navbar-menu {
  display: flex;
  align-items: center;
  list-style: none;
  gap: var(--spacing-sm);
  margin: 0;
  padding: 0;
}

.navbar-item {
  position: relative;
  height: 70px;
  display: flex;
  align-items: center;
}

.navbar-link {
  display: flex;
  align-items: center;
  height: 100%;
  padding: 0 var(--spacing-lg);
  color: var(--color-text-dark);
  text-decoration: none;
  font-weight: var(--font-weight-medium);
  transition: var(--transition-fast);
  border-bottom: 3px solid transparent;
}

.navbar-link:hover {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  background-color: var(--color-background-light);
}

/* 二级菜单 */
.submenu {
  position: absolute;
  top: 100%;
  left: 0;
  background-color: var(--color-background-white);
  list-style: none;
  margin: 0;
  padding: 0;
  min-width: 200px;
  box-shadow: var(--box-shadow-md);
  border-radius: 0 0 var(--border-radius-large) var(--border-radius-large);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.3s ease;
  pointer-events: none;
}

.navbar-item:hover .submenu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  pointer-events: auto;
}

.submenu-item {
  margin: 0;
}

.submenu-link {
  display: block;
  padding: var(--spacing-md) var(--spacing-lg);
  color: var(--color-text-dark);
  text-decoration: none;
  transition: var(--transition-fast);
  border-left: 4px solid transparent;
}

.submenu-link:hover {
  background-color: var(--color-background-light);
  color: var(--color-primary);
  border-left-color: var(--color-primary);
}

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

.navbar-actions .btn {
  height: 42px;
  line-height: 1;
  padding: 0 var(--spacing-md);
}

.navbar-btn {
  padding: var(--spacing-sm) var(--spacing-lg);
  background-color: var(--color-primary);
  color: var(--color-background-white);
  border: none;
  border-radius: var(--border-radius-base);
  cursor: pointer;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  transition: var(--transition-fast);
}

.navbar-btn:hover {
  background-color: var(--color-primary-light);
  box-shadow: var(--box-shadow-hover);
  transform: translateY(-2px);
}

/* 汉堡菜单按钮（移动设备） */
.navbar-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-md);
  color: var(--color-text-dark);
  font-size: 1.5rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
  .navbar-container {
    padding: 0 var(--spacing-md);
    height: 60px;
  }

  .navbar-toggle {
    display: block;
  }

  .navbar-menu {
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--color-background-white);
    box-shadow: var(--box-shadow-md);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .navbar-menu.active {
    max-height: 1000px;
  }

  .navbar-item {
    height: auto;
    border-bottom: var(--border-width) var(--border-style) var(--color-border);
  }

  .navbar-link {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: none;
    height: auto;
  }

  .submenu {
    position: static;
    opacity: 0;
    visibility: hidden;
    max-height: 0;
    overflow: hidden;
    box-shadow: none;
    border-radius: 0;
    transform: none;
    transition: all 0.3s ease;
  }

  .navbar-item:hover .submenu {
    opacity: 0;
    visibility: hidden;
    max-height: 0;
  }

  .submenu--open {
    opacity: 1;
    visibility: visible;
    max-height: 300px;
  }

  .submenu-link {
    padding: var(--spacing-sm) var(--spacing-lg) var(--spacing-sm) calc(var(--spacing-lg) * 2);
  }

  .navbar-logo img {
    height: 40px;
  }

  .navbar-actions {
    gap: var(--spacing-sm);
  }

  .navbar-btn {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: var(--font-size-small);
  }
}

@media (max-width: 480px) {
  .navbar-container {
    height: 50px;
  }

  .navbar-logo {
    font-size: 1rem;
  }

  .navbar-logo img {
    height: 35px;
  }

  .navbar-link {
    padding: 0 var(--spacing-md);
  }

  .submenu-link {
    padding: var(--spacing-sm) var(--spacing-md) var(--spacing-sm) var(--spacing-lg);
  }
}

/* 页面主体内容需要向下偏移以避免被导航栏遮挡 */
body {
  padding-top: 70px;
}

@media (max-width: 768px) {
  body {
    padding-top: 60px;
  }
}

@media (max-width: 480px) {
  body {
    padding-top: 50px;
  }
}