/* --- 基础重置 --- */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            background-color: #f3ebd8;
            color: #111;
            font-family: 'Playfair Display', 'Noto Serif', serif;
            line-height: 1.4;
            -webkit-font-smoothing: antialiased;
            overflow-x: hidden; /* 防止手机端横向滚动 */
        }

        a {
            text-decoration: none;
            color: inherit;
        }

        ul {
            list-style: none;
        }

        /* 主容器：电脑端固定 1350px 居中；手机端宽度自适应 */
        .wrapper {
            width: 1350px;
            margin: 0 auto;
            position: relative;
        }

        /* --- 顶部导航栏 --- */
        header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 28px 40px;
            font-family: 'Noto Serif', sans-serif;
            font-size: 15px;
            width: 100%;
            position: absolute;
            top: 0;
            left: 0;
            z-index: 100;
            font-family: 'Roboto', sans-serif;
        }

        .logo {
            font-family: 'Playfair Display', serif;
            font-weight: 700;
            font-size: 18px;
            letter-spacing: 0.2px;
            font-family: 'Roboto', sans-serif;
        }

        .nav-menu {
            display: flex;
            gap: 32px;
            align-items: center;
        }

        .nav-menu li {
            display: flex;
            align-items: center;
            gap: 6px;
            cursor: pointer;
            font-weight: 400;
        }

        .nav-menu li::after {
            content: "";
            display: inline-block;
            width: 0;
            height: 0;
            border-left: 4.5px solid transparent;
            border-right: 4.5px solid transparent;
            border-top: 5.5px solid #111;
            margin-top: 2px;
        }

        .nav-menu li.no-arrow::after {
            display: none;
        }

        .auth-section {
            display: flex;
            align-items: center;
            gap: 28px;
        }

        .btn-signup {
            background-color: #0d52d6;
            color: #ffffff;
            padding: 10px 20px;
            border-radius: 4px;
            font-weight: 600;
            font-size: 14px;
            letter-spacing: 0.3px;
        }

        /* --- 排版系统 --- */
        h1 {
            font-size: 64px;
            font-weight: 700;
            line-height: 1.05;
            letter-spacing: -1.5px;
            margin-bottom: 28px;
            font-family: 'Roboto', sans-serif;
        }

        h2 {
            font-size: 46px;
            font-weight: 700;
            line-height: 1.15;
            letter-spacing: -1px;
            margin-bottom: 20px;
            font-family: 'Roboto', sans-serif;
        }

        h3 {
            font-size: 32px;
            font-weight: 700;
            margin-bottom: 20px;
            font-family: 'Roboto', sans-serif;
        }

        p {
            font-size: 19px;
            color: #222;
            line-height: 1.6;
            margin-bottom: 28px;
            font-family: 'Noto Serif', serif;
            font-family: 'Roboto', sans-serif;
        }

        .img-box {
            display: block;
            overflow: hidden;
            position: relative;
        }
        
        .img-box img {
            width: 100%;
            height: 100%;
            object-fit: contain;
            display: block;
        }

        /* --- 电脑端：每页满屏 --- */
        main > section {
            height: 100vh;
            min-height: 780px; 
            padding: 120px 0 80px 0;
            display: flex;
            align-items: center; 
            margin-bottom: 0;
        }
        
        .hero {
            padding-top: 160px;
            padding-bottom: 120px;
        }

        /* --- 1. Hero 区域 --- */
        .hero {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .hero-left {
            width: 58%;
        }

        .hero-form {
            display: flex;
            margin-top: 40px;
            gap: 16px;
        }

        .hero-form input {
            padding: 16px 20px;
            border: 1px solid #888;
            background-color: transparent;
            border-radius: 4px;
            width: 320px;
            font-family: 'Noto Serif', sans-serif;
            font-size: 15px;
            color: #111;
            outline: none;
            font-family: 'Roboto', sans-serif;
        }
        
        .hero-form input::placeholder {
            color: #333;
        }

        .hero-form button {
            background-color: #0d52d6;
            color: #fff;
            border: none;
            padding: 16px 28px;
            border-radius: 4px;
            font-weight: 600;
            font-size: 15px;
            cursor: pointer;
            font-family: 'Noto Serif', sans-serif;
            font-family: 'Roboto', sans-serif;
        }

        .hero-right {
            width: 38%;
            display: flex;
            flex-direction: column;
            gap: 45px;
            padding-top: 15px;
        }

        .action-item {
            display: flex;
            align-items: center;
            gap: 24px;
        }

        .black-circle {
            width: 64px;
            height: 64px;
            background-color: #000;
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            flex-shrink: 0;
        }

        .black-circle svg {
            width: 26px;
            height: 26px;
            fill: #fff;
            margin-left: 3px;
        }
        
        .black-circle.arrow svg {
            margin-left: 0;
            margin-top: 1px;
        }

        .action-text {
            font-size: 24px;
            font-weight: 700;
            line-height: 1.15;
            width: 180px;
            font-family: 'Roboto', sans-serif;
        }

        /* --- 2. Preserve 区域 --- */
        .preserve {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .preserve-left {
            width: 48%; 
        }

        .preserve-img-box {
            width: 48%;
            height: 520px;
        }

        /* --- 3. Dialect Audio 区域 --- */
        .dialect {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .dialect-text {
            width: 50%;
            padding-right: 20px;
        }

        .dialect-img-box {
            width: 46%;
            height: 520px;
            border-radius: 50%;
            flex-shrink: 0;
        }

        /* --- 4. Illustrated Stories 区域 --- */
        .stories {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .stories-img-box {
            width: 48%;
            height: 460px;
        }

        .stories-text {
            width: 50%;
            text-align: right;
        }

        .stories-text h2 {
            text-align: right;
        }

        .stories-text p {
            text-align: right;
        }

        /* --- 5. Folk Culture Notes 区域 --- */
        .folk {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .folk-header {
            width: 48%;
        }

        .folk-full-img-box {
            width: 50%;
            height: 560px;
        }

        /* --- 6. Selected Rhymes (双人图) 区域 --- */
        .selected-rhymes {
            display: flex;
            justify-content: space-between;
            align-items: center;
            text-align: center;
            width: 100%;
        }

        .selected-rhymes .dual-img-box {
            width: 300px;
            height: 400px;
            flex-shrink: 0;
        }

        .selected-rhymes .middle-text {
            width: 550px;
            padding: 0 20px;
            text-align: center;
        }

        .selected-rhymes .middle-text h3 {
            margin-bottom: 24px;
        }
        
        .selected-rhymes .middle-text p {
            margin: 0 auto;
            max-width: 500px;
        }

        /* --- 7. Selected Rhymes (视频) 区域 --- */
        .video-section {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .video-text {
            width: 50%;
        }

        .video-circle-box {
            width: 46%;
            height: 520px;
            border-radius: 50%;
            position: relative;
            flex-shrink: 0;
        }

        .video-play-btn {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            width: 70px;
            height: 70px;
            background-color: rgba(0, 0, 0, 0.6);
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        .video-play-btn svg {
            width: 28px;
            height: 28px;
            fill: #fff;
            margin-left: 3px;
        }

        /* --- 8. 底部横幅区域 --- */
        .bottom-banner {
            display: flex;
            justify-content: space-between;
            align-items: center; 
            gap: 40px;
        }

        .banner-img-box {
            width: 46%;
            height: 520px;
            flex-shrink: 0;
        }

        .banner-text-container {
            display: flex;
            justify-content: space-between;
            align-items: center; 
            flex: 1;
        }

        .banner-text-container p {
            width: 320px;
            margin-bottom: 0;
            font-size: 17px; 
        }

        .banner-title {
            font-size: 42px;
            font-weight: 700;
            line-height: 1.1;
            letter-spacing: -0.8px;
            text-align: left;
            white-space: nowrap;
            font-family: 'Roboto', sans-serif;
        }

        /* --- 页脚 --- */
        footer {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 40px 40px;
            font-family: 'Noto Serif', sans-serif;
            font-size: 13px;
            color: #111;
            font-family: 'Roboto', sans-serif;
        }

        .footer-links {
            display: flex;
            gap: 32px;
        }

        /* ========================================================= */
        /* 移动端适配 (手机屏幕宽度小于 900px 时生效)                  */
        /* ========================================================= */
        @media (max-width: 900px) {
            /* 1. 通用重置 */
            body {
                min-width: auto;
            }
            
            .wrapper {
                width: 100%; /* 宽度占满手机屏幕 */
                padding: 0 20px;
            }

            /* 2. 导航栏：改为纵向堆叠 */
            header {
                position: relative; /* 取消悬浮 */
                flex-direction: column;
                padding: 20px 15px;
                gap: 20px;
                background-color: #f3ebd8; /* 避免覆盖内容 */
            }
            
            .nav-menu {
                gap: 15px;
                flex-wrap: wrap;
                justify-content: center;
                font-size: 13px;
            }
            
            .auth-section {
                gap: 15px;
                font-size: 13px;
            }

            /* 3. 每一页取消 100vh，改为内容自适应高度 */
            main > section {
                height: auto; /* 关键：高度随内容自动撑开 */
                min-height: auto;
                padding: 60px 0; /* 减小上下内边距 */
                flex-direction: column; /* 所有区块改为垂直排列 */
                justify-content: center;
                gap: 40px;
            }

            /* 4. 字体全面缩小以适应手机 */
            h1 {
                font-size: 38px;
                letter-spacing: -0.5px;
                text-align: center;
                font-family: 'Roboto', sans-serif;
            }
            h2 {
                font-size: 30px;
                letter-spacing: -0.5px;
                text-align: center;
                font-family: 'Roboto', sans-serif;
            }
            h3 {
                font-size: 24px;
                text-align: center;
                font-family: 'Roboto', sans-serif;
            }
            p {
                font-size: 16px;
                text-align: center;
                line-height: 1.7;
                margin-bottom: 20px;
                font-family: 'Roboto', sans-serif;
            }

            /* 5. 所有文字容器宽度变为 100% */
            .hero-left, .hero-right, 
            .preserve-left, .preserve-img-box,
            .dialect-text, .dialect-img-box,
            .stories-img-box, .stories-text,
            .folk-header, .folk-full-img-box,
            .selected-rhymes .middle-text, 
            .video-text, .video-circle-box,
            .banner-img-box, .banner-text-container,
            .banner-text-container p, .banner-title {
                width: 100%;
                padding: 0;
            }

            /* 6. 恢复部分区域的对齐方式 */
            .stories-text {
                text-align: center;
            }
            .stories-text h2, .stories-text p {
                text-align: center;
            }

            /* 7. 图片容器尺寸调整 */
            .img-box, .preserve-img-box, .dialect-img-box, 
            .stories-img-box, .folk-full-img-box,
            .video-circle-box, .banner-img-box,
            .dual-img-box {
                height: auto;
                max-height: 400px; /* 限制图片最大高度，防止图片过长 */
                width: 100%;
                border-radius: 8px; /* 手机端给图片圆角更好看 */
            }
            
            /* 圆形图片在手机端也可以保持圆形，但缩小一点 */
            .dialect-img-box, .video-circle-box {
                border-radius: 50%;
                height: auto;
                aspect-ratio: 1/1; /* 强制正方形以保持圆形 */
                max-width: 320px;
                margin: 0 auto;
            }

            /* 8. 双人图区域手机端改为纵向 */
            .selected-rhymes {
                flex-direction: column;
                gap: 30px;
            }
            .selected-rhymes .dual-img-box {
                max-width: 280px;
                height: auto;
                aspect-ratio: 1/1;
                margin: 0 auto;
                border-radius: 8px;
            }

            /* 9. 底部横幅区域手机端垂直居中 */
            .bottom-banner {
                flex-direction: column;
                align-items: center;
                gap: 30px;
                text-align: center;
            }
            .banner-text-container {
                flex-direction: column;
                align-items: center;
                gap: 20px;
                text-align: center;
            }
            .banner-title {
                white-space: normal; /* 手机端允许标题换行 */
                text-align: center;
            }
            
            .banner-img-box {
                max-height: 350px;
            }

            /* 10. Hero 区域和按钮 */
            .hero-form {
                flex-direction: column;
                align-items: center;
                width: 100%;
            }
            .hero-form input {
                width: 100%;
                max-width: 300px;
            }
            .hero-form button {
                width: 100%;
                max-width: 300px;
            }

            .hero-right {
                align-items: center;
            }
            .action-item {
                justify-content: center;
            }
            .action-text {
                width: auto;
                text-align: center;
                font-size: 18px;
                font-family: 'Roboto', sans-serif;
            }

            /* 11. 页脚改为纵向 */
            footer {
                flex-direction: column;
                gap: 20px;
                text-align: center;
                padding: 30px 20px;
            }
            .footer-links {
                flex-wrap: wrap;
                justify-content: center;
                gap: 15px;
            }
        }