/* 头部导航样式 */
header {
    background-color: rgba(0, 0, 0, 0.9);
    height: 70px;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    height: 100%;
}

.logo {
    display: flex;
    align-items: center;
}

.logo span,
.logo a {
    color: #fff;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    gap: 30px;
}

.nav-menu li a {
    font-size: 16px;
    font-weight: 600;
    color: #fff;
    transition: all 0.3s ease;
    position: relative;
    padding: 5px 0;
}

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

.nav-menu li a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: #3498db;
    transition: width 0.3s ease;
}

.nav-menu li a:hover::after {
    width: 100%;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: #333;
    cursor: pointer;
}

/* 响应式导航 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 100px;
        left: -100%;
        flex-direction: column;
        background-color: #fff;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
        padding: 20px 0;
    }

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

    .nav-menu.active li a {
        color: #333;
    }

    .nav-menu li {
        margin: 15px 0;
    }

    .mobile-menu-btn {
        display: block;
        color: #fff;
    }
}

@media (max-width: 576px) {
    /* 移动端Logo样式 */
}