@media (max-width: 768px) {
    .header {
        padding: 20px 20px;
        justify-content: center;
    }

    .header .logo {
        position: static;
        font-size: 18px;
    }

    .header .language-switcher {
        display: none;
    }

    .header .language-switcher a {
        color: #fff;
        text-decoration: none;
    }

    .header .menu {
        display: none;
    }

    .header .menu-btn {
        display: block;
        position: absolute;
        right: 20px;
        font-size: 24px;
        color: #fff;
        cursor: pointer;
    }

    .fullscreen-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(0, 0, 0, 0.95);
        z-index: 200;
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        opacity: 0;
        visibility: hidden;
        transition: opacity 0.3s ease, visibility 0.3s ease;
    }

    .fullscreen-menu.active {
        opacity: 1;
        visibility: visible;
    }

    .fullscreen-menu .close-btn {
        position: absolute;
        top: 20px;
        right: 20px;
        font-size: 28px;
        color: #fff;
        cursor: pointer;
    }

    .fullscreen-menu nav {
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 30px;
        font-size: 20px;
        color: #fff;
        margin-bottom: 40px;
    }

    .fullscreen-menu nav a {
        text-decoration: none;
        color: inherit;
        position: relative;
    }

    .fullscreen-menu nav a.active {
        font-weight: bold;
    }

    .fullscreen-menu nav a.active::after {
        content: '';
        position: absolute;
        bottom: -8px;
        left: 50%;
        transform: translateX(-50%);
        width: 20px;
        height: 2px;
        background-color: #fff;
    }

    .fullscreen-menu .language-switcher {
        font-size: 16px;
    }

    .fullscreen-menu .language-switcher a {
        color: #fff;
        text-decoration: none;
    }

    /* ===== 通用 ===== */
    .section-first,
    .section-second,
    .section-third,
    .section-fourth,
    .section-fifth {
        height: 100dvh;
    }

    .section-title {
        font-size: 32px;
    }

    .more-link {
        font-size: 13px;
    }

    .more-link-sub {
        font-size: 13px;
    }

    .more-link-sub span {
        font-size: 11px;
    }

    /* ===== 第一页 ===== */
    .section-first .center-content .title {
        font-size: 32px;
    }

    .section-first .center-content .subtitle {
        font-size: 16px;
    }

    .section-first .scroll-hint span {
        font-size: 10px;
    }

    /* ===== 第二页 ===== */
    .section-second .section-content {
        padding: 0 28px;
    }

    .section-second .section-content p {
        font-size: 14px;
        line-height: 2;
        max-width: 100%;
        margin-bottom: 12px;
    }

    /* ===== 第三页 ===== */
    .section-third .section-container {
        padding: 0 28px;
    }

    .section-third .content-split {
        flex-direction: column;
        align-items: center;
        gap: 40px;
    }

    .section-third .left-text {
        width: 100%;
    }

    .section-third .left-text p {
        font-size: 14px;
        line-height: 2;
        text-align: center;
    }

    .section-third .left-text p.gap {
        margin-top: 24px;
    }

    .section-third .right-cards {
        width: 100%;
        align-items: center;
        gap: 28px;
    }

    .section-third .product-card {
        width: 100%;
        max-width: 400px;
        gap: 12px;
    }

    .section-third .card-icon {
        width: 42px;
        height: 42px;
        border-radius: 10px;
    }

    .section-third .card-info h3 {
        font-size: 16px;
    }

    .section-third .card-info p {
        font-size: 13px;
    }

    .section-third .card-link {
        font-size: 13px;
    }

    /* ===== 第四页 ===== */
    .section-fourth .section-content {
        padding: 0 28px;
    }

    .section-fourth .section-content p {
        font-size: 14px;
        line-height: 2;
        max-width: 100%;
    }

    .section-fourth .section-content p.gap {
        margin-top: 24px;
    }

    .section-fourth .design-links {
        gap: 40px;
    }

    .section-fourth .design-link {
        font-size: 13px;
    }

    .section-fourth .design-link i {
        font-size: 28px;
    }

    /* ===== 第五页 ===== */
    .section-fifth .footer-box {
        height: auto;
        min-height: 55%;
        padding: 40px 28px;
        gap: 24px;
    }

    .back-to-top i {
        font-size: 48px;
    }

    .footer-logo {
        font-size: 32px;
    }

    .footer-menu {
        gap: 20px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .footer-menu a {
        font-size: 14px;
    }

    .footer-links {
        gap: 18px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .footer-links a {
        font-size: 13px;
    }

    .footer-social {
        gap: 28px;
    }

    .social-icon {
        font-size: 24px;
    }

    .footer-beian a {
        font-size: 12px;
    }

    .footer-credit {
        font-size: 13px;
    }

    .footer-copyright {
        font-size: 12px;
    }

    /* WeChat Modal */
    .wechat-modal-content {
        padding: 32px 28px;
        margin: 0 24px;
    }

    .wechat-modal-content p {
        font-size: 16px;
    }

    .wechat-modal-content .wechat-note {
        font-size: 13px;
    }
}