/* 主导航样式 */
.main-nav {
    position: relative;
    margin-left: auto;
}

.main-nav > ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: 20px;
}

.main-nav > ul > li {
    position: relative;
}

/* 导航菜单容器 */
.nav-menu-container {
    position: fixed;
    top: 64px; /* header 高度 */
    left: 0;
    width: 100%;
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s ease, visibility 0.2s ease;
    z-index: 1000;
}

.nav-menu-container.active {
    opacity: 1;
    visibility: visible;
}

/* 导航菜单内容 */
.nav-menu-content {
    max-width: 1440px;
    margin: 0 auto;
    padding: 40px;
    display: flex;
    gap: 40px;
}

.menu-columns {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.menu-column h3 {
    font-size: 14px;
    font-weight: 600;
    color: #666;
    margin-bottom: 20px;
    text-transform: uppercase;
}

.menu-column ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.menu-column li {
    margin-bottom: 12px;
}

.menu-column a {
    display: block;
    padding: 8px 0;
    color: #000;
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s ease;
}

.menu-column a:hover {
    color: #003366;
}

.menu-featured {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    width: 400px;
}

.featured-item {
    display: block;
    text-decoration: none;
    color: #000;
    transition: transform 0.2s ease;
}

.featured-item:hover {
    transform: translateY(-4px);
}

.featured-item img {
    width: 100%;
    height: 160px;
    object-fit: cover;
    border-radius: 8px;
    margin-bottom: 10px;
}

.featured-item span {
    font-size: 14px;
    font-weight: 500;
}

/* 激活状态的导航项 */
.main-nav > ul > li.active > a {
    color: #fff;
}

.main-nav > ul > li.active > a::after {
    transform: scaleX(1);
}

/* 图片预览区域 */
.nav-preview {
    grid-column: 3 / span 2;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.preview-card {
    position: relative;
    overflow: hidden;
    border-radius: 12px;
    aspect-ratio: 16/9;
}

.preview-card img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.preview-card:hover img {
    transform: scale(1.05);
}

.preview-card .preview-content {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 20px;
    background: linear-gradient(transparent, rgba(0,0,0,0.7));
    color: #fff;
}

.preview-content h4 {
    font-size: 18px;
    margin-bottom: 8px;
}

.preview-content p {
    font-size: 14px;
    opacity: 0.8;
}

/* 如果需要为 About Us 子菜单添加特殊样式 */
.about-submenu {
    min-width: 180px; /* 调整宽度 */
}

.about-submenu ul {
    padding: 10px 0;
}

.about-submenu li {
    padding: 8px 20px;
}

.about-submenu li a {
    color: #333;
    font-size: 14px;
    text-decoration: none;
    display: block;
    transition: color 0.3s;
}

.about-submenu li a:hover {
    /* color: #003366; */ /* 删除或注释掉这行 */
}

@media (max-width: 768px) {
    .about-submenu {
        position: static;
        width: 100%;
        box-shadow: none;
        background: transparent;
    }

    .about-submenu li {
        padding: 8px 30px;
    }
}

/* 如果有其他子菜单悬浮样式也需要删除 */
.submenu li a:hover {
    /* color: #003366; */ /* 删除或注释掉这行 */
}

/* 删除 Products 子菜单的悬浮背景样式 */
.product-submenu li:hover {
    background: none;
}

.product-submenu li a:hover {
    background: none;
}

.product-submenu ul li:hover {
    background: none;
}

.product-submenu ul li a:hover {
    background: none;
}

/* 子菜单样式 */
.submenu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    background: #fff;
    min-width: 200px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    border-radius: 4px;
    z-index: 1000;
}

/* Products 子菜单特殊样式 */
.product-submenu {
    min-width: 220px;
}

.product-submenu ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.product-submenu li {
    position: relative;
}

.product-submenu li a {
    padding: 10px 20px;
    display: block;
    color: #333;
    text-decoration: none;
    transition: background-color 0.3s, color 0.3s;
}

/* 二级菜单 */
.product-submenu ul ul {
    display: none;
    position: absolute;
    left: 100%;
    top: 0;
    background: #fff;
    min-width: 200px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    border-radius: 4px;
}

/* 三级菜单 */
.product-submenu ul ul ul {
    left: 100%;
    top: 0;
}

/* 显示子菜单 */
.has-submenu:hover > .submenu {
    display: block;
}

.product-submenu li:hover > ul {
    display: block;
}

/* 菜单项悬浮效果 */
.product-submenu li:hover > a {
    background-color: #f5f7fa;
    color: #003366;
}

/* 添加箭头指示器 */
.product-submenu li:has(> ul) > a::after {
    content: '›';
    position: absolute;
    right: 15px;
    transform: rotate(0deg);
    transition: transform 0.3s;
}

.product-submenu li:has(> ul):hover > a::after {
    transform: rotate(90deg);
}

/* 动画效果 */
.submenu,
.product-submenu ul ul {
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
}

.has-submenu:hover > .submenu,
.product-submenu li:hover > ul {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* 响应式调整 */
@media (max-width: 768px) {
    .product-submenu,
    .product-submenu ul ul {
        position: static;
        width: 100%;
        box-shadow: none;
        opacity: 1;
        visibility: visible;
        transform: none;
    }

    .product-submenu li a {
        padding-left: 30px;
    }

    .product-submenu ul ul li a {
        padding-left: 45px;
    }

    .product-submenu ul ul ul li a {
        padding-left: 60px;
    }
}

/* 保持联系信息样式 */
.contact-info {
    margin-bottom: 20px;
}

.contact-item {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: inherit;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .submenu {
        position: static;
        box-shadow: none;
        width: 100%;
    }

    .submenu ul {
        position: static;
        box-shadow: none;
        width: 100%;
        padding-left: 20px;
    }
}