/* 全局重置 */
body { margin: 0; padding: 0; }

/* 主导航 */
.top-nav {
    width: 100%;
    height: 70px;
    background: #ffffff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    left: 0;
    z-index: 1000;
    margin: 0;
    padding: 0;
}

.nav-wrap {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 50px;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
    text-decoration: none;
    flex-shrink: 0;
}

.logo img {
    height: 40px;
    width: auto;
    display: block;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 4px;
    list-style: none;
    margin: 0;
    padding: 0;
    flex-shrink: 0;
}

.nav-menu li {
    position: relative;
    height: 70px;
    display: flex;
    align-items: center;
}

.nav-menu a {
    padding: 0 14px;
    color: #1F2937;
    font-size: 15px;
    font-weight: 500;
    white-space: nowrap;
    text-decoration: none;
    transition: color 0.2s;
}

.nav-menu a:hover {
    color: #F97316;
}

.nav-menu > li.has-sub > a::after {
    content: "▼";
    font-size: 10px;
    margin-left: 4px;
}

.sub-menu {
    position: absolute;
    top: 70px;
    left: 50%;
    transform: translateX(-50%);
    background: #ffffff;
    border-radius: 8px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    min-width: 160px;
    padding: 8px 0;
    display: none;
    z-index: 999;
    list-style: none;
}

.sub-menu li a {
    display: block;
    padding: 10px 20px;
    color: #1F2937;
    font-size: 14px;
}

.sub-menu li a:hover {
    background: #EFF6FF;
    color: #1E40AF;
}

.nav-menu > li:hover .sub-menu {
    display: block;
}

/* 移动端适配 */
@media (max-width: 768px) {
    .nav-wrap {
        flex-direction: column;
        gap: 10px;
        height: auto;
        padding: 10px 20px;
    }
    .nav-menu {
        flex-wrap: wrap;
        justify-content: center;
    }
    .nav-menu li {
        height: auto;
    }
    .nav-menu a {
        padding: 8px 10px;
        font-size: 13px;
    }
}