/* 导航 桌面基础样式 */
.nav-main {
    background-color: #ffffff;
    width: 100%;
}
.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
    display: flex;
    align-items: center;
    position: relative;
}
.all-category-item {
    width: 20%;
    flex: 0 0 20%;
}
.nav-items {
    display: flex;
    flex: 1;
}
.nav-items .nav-item {
    flex: 1;
    text-align: center;
}
.nav-link {
    color: #222;
    padding: 16px 0;
    font-size: 15px;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    border: none !important;
}
.all-category-link {
    background-color: #0066cc;
    color: #fff !important;
    justify-content: flex-start;
    padding-left: 20px;
}
.nav-link:hover:not(.all-category-link) {
    background-color: #0066cc;
    color: #fff !important;
}

/* 汉堡按钮 默认隐藏（桌面端） */
.nav-hamburger {
    display: none;
    width: 44px;
    height: 44px;
    background: transparent;
    border: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 6px;
    cursor: pointer;
}
.nav-hamburger span {
    display: block;
    width: 24px;
    height: 3px;
    background: #222;
    border-radius: 2px;
    transition: all 0.2s ease;
}
.nav-item-sy {
    display: none;
}

/* 移动端适配阈值：≤992px 显示汉堡，隐藏横向菜单 */
@media screen and (max-width: 768px) {
    .nav-container {
        justify-content: space-between;
    }
    /* 左侧分类缩小宽度 */
    .all-category-item {
        flex: 0 0 160px;
        width: auto;
    }
    /* 显示汉堡按钮 */
    .nav-hamburger, .nav-item-sy{
        display: flex;
    }
    /* 横向菜单改为垂直下拉，默认隐藏 */
    .nav-items {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: #fff;
        flex-direction: column;
        display: none;
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        z-index: 99;
    }
    /* 菜单展开类 */
    .nav-items.show {
        display: flex;
    }
    /* 移动端每个导航项占满宽度 */
    .nav-items .nav-item {
        flex: none;
        width: 100%;
    }
    .nav-items .nav-link {
        justify-content: center;
        padding: 14px 20px;
    }
    .nav-item-sy .nav-link {
        width: 100%;
    }
}