/* 导航栏样式 */
#header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: #ffffff;
    box-shadow: var(--shadow);
    z-index: 1000;
    transition: var(--transition);
}

#header.scrolled {
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.1);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

/* Logo样式 */
.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.logo-img {
    height: 40px;
    width: auto;
    object-fit: contain;
    max-width: 200px;
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

/* 导航菜单 */
.nav-menu {
    display: flex;
    gap: 30px;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-link {
    font-size: 15px;
    font-weight: 500;
    color: var(--dark-color);
    text-decoration: none;
    padding: 8px 0;
    position: relative;
    transition: var(--transition);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    transition: var(--transition);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

/* 汉堡菜单按钮 */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
}

.hamburger .line {
    width: 25px;
    height: 2px;
    background: var(--dark-color);
    transition: var(--transition);
}

.hamburger.active .line:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active .line:nth-child(2) {
    opacity: 0;
}

.hamburger.active .line:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* 响应式导航 */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: #ffffff;
        flex-direction: column;
        gap: 0;
        padding: 20px;
        transition: var(--transition);
        box-shadow: var(--shadow);
        overflow-y: auto;
    }

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

    .nav-link {
        padding: 15px;
        border-bottom: 1px solid var(--border-color);
        display: block;
    }

    .nav-link::after {
        display: none;
    }
}