/* 导航箭头样式 */
.submenu-arrow {
  margin-left: 4px;
  font-size: 12px;
  transition: transform 0.3s ease;
  display: inline-block;
  vertical-align: middle;
}

/* 有子菜单的导航项 */
.has-submenu > a {
  display: inline-flex;
  align-items: center;
}

/* 箭头旋转动画 - 当二级菜单打开时 */
.has-submenu.active .submenu-arrow {
  transform: rotate(180deg);
}

/* 二级菜单容器样式 */
.nav-submenu-container {
  position: fixed;
  top: 65px;
  left: 0;
  right: 0;
  background: #fff;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  z-index: 999;
  display: none;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, opacity 0.3s ease;
  opacity: 0;
}

.nav-submenu-container.active {
  display: block;
  max-height: 500px;
  opacity: 1;
}

/* 二级菜单项 */
.nav-submenu {
  display: none;
  padding: 30px 0;
}

.nav-submenu.active {
  display: block;
}

.nav-submenu-empty {
  display: none !important;
}

/* 二级菜单内容区域 */
.submenu-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

/* 二级菜单单项 */
.submenu-item {
  display: flex;
  align-items: flex-start;
  padding: 16px;
  border-radius: 8px;
  text-decoration: none;
  color: #333;
  transition: all 0.3s ease;
  background: #f8f9fa;
  border: 1px solid transparent;
}

.submenu-item:hover {
  background: #fff;
  border-color: #0052d9;
  box-shadow: 0 2px 8px rgba(0, 82, 217, 0.1);
  transform: translateY(-2px);
}

/* 二级菜单图标 */
.submenu-icon {
  width: 40px;
  height: 40px;
  margin-right: 12px;
  flex-shrink: 0;
  object-fit: contain;
}

/* 二级菜单文本 */
.submenu-text {
  flex: 1;
}

.submenu-title {
  font-size: 15px;
  font-weight: 600;
  color: #333;
  margin-bottom: 4px;
  line-height: 1.4;
}

.submenu-desc {
  font-size: 13px;
  color: #666;
  line-height: 1.5;
}

.submenu-item:hover .submenu-title {
  color: #0052d9;
}

/* 动画效果 */
@keyframes slideInDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animated.slideInDown {
  animation: slideInDown 0.3s ease;
}

/* 响应式设计 */
@media (max-width: 1024px) {
  .submenu-content {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 15px;
  }
}

@media (max-width: 768px) {
  .nav-submenu-container {
    position: static;
    box-shadow: none;
    border-top: 1px solid #e0e0e0;
  }
  
  .submenu-content {
    grid-template-columns: 1fr;
    gap: 10px;
    padding: 15px;
  }
  
  .nav-submenu {
    padding: 15px 0;
  }
  
  .submenu-item {
    padding: 12px;
  }
  
  .submenu-icon {
    width: 32px;
    height: 32px;
  }
}

/* 移动端隐藏二级菜单 */
@media (max-width: 768px) {
  .nav-submenu-container {
    display: none !important;
  }
}