:root {
            --red: #ef443b;
            --red-dark: #c0392b;
            --orange: #ee5a3b;
            --text: #1a1a1a;
            --text2: #4a4a4a;
            --gray-light: #f7f8fa;
            --gray-border: #e8eaef;
            --white: #fff;
            --radius: 16px;
            --radius-sm: 8px;
            --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
            --shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
            --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.10);
            --transition: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
            --max-w: 1280px;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, sans-serif;
            color: var(--text);
            background: #fefefe;
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
        }
        a {
            text-decoration: none;
            color: inherit;
        }
        ul {
            list-style: none;
        }

        /* ===== 导航栏（与首页完全一致） ===== */
        .nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            background: rgba(255, 255, 255, 0.88);
            backdrop-filter: blur(14px);
            -webkit-backdrop-filter: blur(14px);
            border-bottom: 1px solid rgba(0, 0, 0, 0.05);
            height: 64px;
            display: flex;
            align-items: center;
            padding: 0 5%;
            justify-content: space-between;
            transition: var(--transition);
        }
        .nav-logo img {
            height: 28px;
            width: auto;
        }
        .nav-links {
            display: flex;
            align-items: center;
            gap: 6px;
            flex-wrap: wrap;
        }
        .nav-links a {
            font-size: 14px;
            font-weight: 500;
            color: #333;
            padding: 8px 14px;
            border-radius: 20px;
            transition: var(--transition);
            white-space: nowrap;
        }
        .nav-links a:hover {
            background: #fff0ef;
            color: var(--red);
        }
        .nav-cta {
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .btn-nav-dl {
            background: var(--red);
            color: #fff;
            font-weight: 600;
            font-size: 14px;
            padding: 9px 20px;
            border-radius: 22px;
            transition: var(--transition);
            white-space: nowrap;
        }
        .btn-nav-dl:hover {
            background: var(--red-dark);
            transform: translateY(-1px);
            box-shadow: 0 4px 14px rgba(239, 68, 59, 0.35);
        }

        /* ===== 下载页首屏 ===== */
        .dl-hero {
            padding: 150px 5% 70px;
            background: radial-gradient(circle at 90% 10%, rgba(239, 68, 68, 0.05) 0%, rgba(255, 255, 255, 1) 50%);
            text-align: center;
        }
        .dl-hero h1 {
            font-size: clamp(2.4rem, 5vw, 3.8rem);
            font-weight: 700;
            margin-bottom: 20px;
        }
        .dl-hero h1 .hl {
            background: linear-gradient(135deg, #ef443b 0%, #ee6b3b 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .dl-hero .hero-desc {
            font-size: 1.15rem;
            max-width: 720px;
            margin: 0 auto 36px;
            color: #4b5563;
            line-height: 1.7;
        }
        .main-dl-card {
            background: #fff;
            border-radius: 24px;
            padding: 45px 50px;
            box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.08);
            display: inline-flex;
            align-items: center;
            gap: 40px;
            border: 1px solid #f3f4f6;
            margin-bottom: 20px;
            flex-wrap: wrap;
            justify-content: center;
            text-align: left;
        }
        .os-info h3 {
            font-size: 1.8rem;
            font-weight: 700;
            margin-bottom: 8px;
        }
        .os-badge {
            display: flex;
            align-items: center;
            gap: 10px;
            color: var(--red);
            font-weight: 700;
            margin-bottom: 15px;
            font-size: 1rem;
        }
        .os-badge img {
            width: 32px;
            height: 32px;
        }
        .btn-dl-large {
            display: inline-block;
            background: var(--red);
            color: #fff;
            padding: 20px 50px;
            border-radius: 12px;
            text-decoration: none;
            font-weight: 700;
            font-size: 1.2rem;
            box-shadow: 0 10px 30px rgba(239, 68, 68, 0.3);
            transition: 0.3s;
            white-space: nowrap;
        }
        .btn-dl-large:hover {
            transform: translateY(-3px);
            box-shadow: 0 15px 35px rgba(239, 68, 68, 0.4);
            background: #d93833;
        }
        .dl-hero .alt-links {
            margin-top: 20px;
            font-size: 0.9rem;
            color: #6b7280;
        }
        .dl-hero .alt-links a {
            color: var(--red);
            text-decoration: none;
            font-weight: 500;
        }
        .dl-hero .alt-links a:hover {
            text-decoration: underline;
        }

        /* ===== 全平台下载卡片 ===== */
        .platform-section {
            padding: 80px 5%;
            background: #fcfcfc;
        }
        .platform-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
            gap: 24px;
            max-width: var(--max-w);
            margin: 0 auto;
        }
        .platform-card {
            background: #fff;
            padding: 28px 24px;
            border-radius: 16px;
            border: 1px solid #eee;
            text-align: center;
            transition: 0.3s;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        .platform-card:hover {
            border-color: var(--red);
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.05);
        }
        .platform-card img {
            width: 48px;
            height: 48px;
            margin-bottom: 16px;
        }
        .platform-card h4 {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: 10px;
            color: var(--text);
        }
        .platform-card .version-tag {
            background: #fff0ef;
            color: var(--red);
            font-size: 0.75rem;
            font-weight: 600;
            padding: 3px 10px;
            border-radius: 12px;
            margin-bottom: 12px;
        }
        .platform-card p {
            color: #4b5563;
            margin-bottom: 16px;
            font-size: 0.9rem;
            line-height: 1.5;
            flex: 1;
        }
        .platform-card .dl-link {
            color: var(--red);
            text-decoration: none;
            font-weight: 600;
            font-size: 0.9rem;
            border-bottom: 1px solid transparent;
            transition: 0.2s;
            display: inline-flex;
            align-items: center;
            gap: 4px;
        }
        .platform-card .dl-link:hover {
            border-bottom: 1px solid var(--red);
        }

        /* ===== 新版亮点 & 更新日志 ===== */
        .highlights-section {
            padding: 80px 5%;
            background: #fff;
            text-align: center;
        }
        .highlights-section h2 {
            font-size: 2.4rem;
            font-weight: 700;
            margin-bottom: 15px;
        }
        .highlights-section h2 .hl {
            color: var(--red);
        }
        .highlights-section .section-subtitle {
            max-width: 650px;
            margin: 0 auto 50px;
            color: #4b5563;
            font-size: 1rem;
            line-height: 1.6;
        }
        .highlights-grid {
            display: flex;
            gap: 24px;
            justify-content: center;
            flex-wrap: wrap;
            margin-bottom: 50px;
            max-width: var(--max-w);
            margin-left: auto;
            margin-right: auto;
        }
        .highlight-item {
            background: #f9fafb;
            padding: 30px 24px;
            border-radius: 20px;
            flex: 1 1 220px;
            max-width: 280px;
            text-align: left;
            transition: 0.3s;
            border: 1px solid transparent;
        }
        .highlight-item:hover {
            background: #fff;
            border-color: #fee;
            box-shadow: 0 12px 28px rgba(0, 0, 0, 0.04);
            transform: translateY(-4px);
        }
        .highlight-item .icon {
            font-size: 2rem;
            margin-bottom: 14px;
        }
        .highlight-item h3 {
            font-size: 1.3rem;
            margin-bottom: 10px;
            font-weight: 700;
            color: var(--text);
        }
        .highlight-item p {
            color: #4b5563;
            font-size: 0.95rem;
            line-height: 1.6;
        }
        .changelog {
            max-width: 800px;
            margin: 0 auto;
            text-align: left;
            background: #fefefe;
            border-radius: 16px;
            padding: 30px 35px;
            border: 1px solid #f0f0f0;
            box-shadow: 0 6px 18px rgba(0, 0, 0, 0.02);
        }
        .changelog h3 {
            font-size: 1.5rem;
            font-weight: 700;
            margin-bottom: 20px;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .changelog ul {
            list-style: none;
        }
        .changelog ul li {
            padding: 10px 0;
            border-bottom: 1px dashed #eee;
            font-size: 0.95rem;
            color: #374151;
            display: flex;
            gap: 8px;
        }
        .changelog ul li::before {
            content: "•";
            color: var(--red);
            font-weight: 700;
        }

        /* ===== 安装指引 ===== */
        .install-guide {
            padding: 70px 5%;
            background: #fcfcfc;
            text-align: center;
        }
        .install-guide h2 {
            font-size: 2.4rem;
            font-weight: 700;
            margin-bottom: 15px;
        }
        .install-guide h2 .hl {
            color: var(--red);
        }
        .steps-grid {
            display: flex;
            gap: 20px;
            justify-content: center;
            flex-wrap: wrap;
            margin-top: 40px;
            max-width: var(--max-w);
            margin-left: auto;
            margin-right: auto;
        }
        .step-card {
            background: #fff;
            border-radius: 16px;
            padding: 28px 20px;
            flex: 1 1 180px;
            max-width: 220px;
            border: 1px solid #eee;
            transition: 0.3s;
            position: relative;
        }
        .step-card:hover {
            border-color: var(--red);
            transform: translateY(-4px);
            box-shadow: 0 12px 30px rgba(0, 0, 0, 0.04);
        }
        .step-num {
            background: var(--red);
            color: #fff;
            width: 36px;
            height: 36px;
            border-radius: 50%;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 1.2rem;
            margin-bottom: 16px;
        }
        .step-card h4 {
            font-weight: 700;
            margin-bottom: 8px;
            font-size: 1.1rem;
        }
        .step-card p {
            font-size: 0.85rem;
            color: #6b7280;
            line-height: 1.5;
        }

        /* ===== 页脚（与首页完全一致） ===== */
        .footer {
            background: #111;
            color: #ccc;
            padding: 60px 5% 30px;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
            gap: 30px;
            max-width: var(--max-w);
            margin: 0 auto;
        }
        .footer-col h4 {
            color: #fff;
            font-size: 1rem;
            font-weight: 700;
            margin-bottom: 16px;
            position: relative;
            padding-bottom: 10px;
        }
        .footer-col h4::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 28px;
            height: 2px;
            background: var(--red);
            border-radius: 1px;
        }
        .footer-col ul li {
            margin-bottom: 8px;
        }
        .footer-col ul li a {
            color: #aaa;
            font-size: 13px;
            transition: var(--transition);
        }
        .footer-col ul li a:hover {
            color: #fff;
        }
        .footer-bottom {
            max-width: var(--max-w);
            margin: 40px auto 0;
            padding-top: 20px;
            border-top: 1px solid #2a2a2a;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 12px;
            font-size: 12px;
            color: #777;
        }
        .footer-bottom a {
            color: #999;
            margin-left: 16px;
            transition: var(--transition);
        }
        .footer-bottom a:hover {
            color: #fff;
        }

        /* ===== 响应式 ===== */
        @media (max-width: 768px) {
            .nav-links {
                display: none;
            }
            .dl-hero h1 {
                font-size: 2.2rem;
            }
            .main-dl-card {
                flex-direction: column;
                padding: 30px 25px;
                text-align: center;
            }
            .os-info {
                text-align: center;
            }
            .btn-dl-large {
                width: 100%;
            }
            .platform-grid {
                grid-template-columns: 1fr;
            }
            .highlights-section h2,
            .install-guide h2 {
                font-size: 2rem;
            }
            .footer-bottom {
                flex-direction: column;
                text-align: center;
            }
        }