.nav-menu {
    display: flex;
    align-items: stretch;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-item {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.nav-link {
    display: block;
    color: #777;
    text-decoration: none;
    padding: 10px 15px 10px;
    font-weight: 500;
    transition: all 0.3s ease;
}

a.nav-link {
    color: #777;
    display: block;
}

a.nav-link:visited {
    color: #777;
}

a.nav-link:hover {
    color: #3498db;
}

.nav-item:hover::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: #3498db;
    border-radius: 3px 3px 0 0;
}

.active {
    color: #3498db;
}

.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: #3498db;
    border-radius: 3px 3px 0 0;
}

.dropdown {
    position: relative;
}

.dropdown-content {
    list-style: none;
    position: absolute;
    margin: 0;
    padding: 0;
    top: 100%;
    left: 0;
    background-color: #fff;
    min-width: unset;
    white-space: nowrap;
    width: auto;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border-radius: 0 0 8px 8px;
    z-index: 1;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
}

.dropdown-content.right {
    right: 0;
    left: auto;
}

.dropdown-content li {
    position: relative;
    display: block;
    padding: 12px 20px;
    color: #777;
    text-decoration: none;
    transition: all 0.3s ease;
}

.dropdown-content li:hover {
    background-color: #f1f1f1;
}

.dropdown-content li.group {
    padding: 12px 20px;
    color: #333;
    font-weight: bold;
}

.dropdown-content li.group:hover {
    background-color: #fff;
}

/* .dropdown-content li:hover::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background-color: #3498db;
    border-radius: 3px 3px 0 0;
} */

.dropdown-content li a {
    color: #777;
    display: block;
}

.dropdown-content li a:visited {
    color: #777;
}

.dropdown-content li a:hover {
    color: #3498db;
}

.dropdown-content li.separator {
    padding: 0;
    height: 1px;
    margin: 1px;
    overflow: hidden;
    background-color: #e5e5e5;
    border-bottom: 1px solid #fff;
}

.dropdown:hover .dropdown-content {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.hamburger {
    display: none;
    cursor: pointer;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: #333;
}

/* 响应式设计 */
@media screen and (max-width: 768px) {
    .hamburger {
        display: block;
    }

    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        background-color: #fff;
        width: 100%;
        height: calc(100vh - 80px);
        flex-direction: column;
        transition: all 0.3s ease;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        padding: 20px 0;
        z-index: 100;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-item {
        display: block;
        width: 100%;
    }

    .nav-link {
        text-decoration: none;
        padding: 15px 20px;
    }

    .dropdown-content {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        display: none;
        padding-left: 20px;
    }

    .dropdown-content li {
        text-decoration: none;
    }

    .dropdown.active .dropdown-content {
        display: block;
    }
}