:root{
            --safe-primary:#0b5fff;
            --safe-primary-dark:#0847c4;
            --safe-accent:#00d4aa;
            --safe-dark:#0d1b2a;
            --safe-darker:#08111c;
            --safe-text:#1f2937;
            --safe-muted:#5b6b7c;
            --safe-bg:#ffffff;
            --safe-bg-alt:#f5f8ff;
            --safe-border:#e6ecf5;
            --safe-radius:20px;
            --safe-shadow:0 12px 30px rgba(11,95,255,.08);
            --safe-transition:.3s cubic-bezier(.4,0,.2,1);
            --font-sans:'Inter','PingFang SC','Microsoft YaHei','Segoe UI',sans-serif;
            /* 关于页面额外变量 */
            --about-accent:#e11d48;
            --about-accent-light:#ffe4e6;
            --about-gradient:linear-gradient(135deg,#0d1b2a 0%,#4c1d95 100%);
            --about-soft-bg:#fdf2f8;
        }
        *{margin:0;padding:0;box-sizing:border-box}
        html{scroll-behavior:smooth}
        body{font-family:var(--font-sans);color:var(--safe-text);background:var(--safe-bg);line-height:1.6;overflow-x:hidden}
        a{text-decoration:none;color:inherit}
        img{max-width:100%;display:block}
        .site{display:flex;flex-direction:column;min-height:100vh}
        .section-wrap{max-width:1200px;margin:0 auto;padding:0 24px}

        /* Header (与首页一致，包含网站地图链接) */
        .site-header{background:rgba(255,255,255,.9);backdrop-filter:blur(12px);position:sticky;top:0;z-index:100;border-bottom:1px solid var(--safe-border)}
        .nav-shell{display:flex;align-items:center;justify-content:space-between;max-width:1200px;margin:0 auto;padding:12px 24px;gap:20px}
        .brand{display:flex;align-items:center;gap:8px;font-weight:800;font-size:1.5rem;color:var(--safe-dark);}
        .brand img{height:40px;width:auto}
        .main-nav{display:flex;align-items:center;gap:28px}
        .main-nav a{font-weight:600;color:var(--safe-text);position:relative;padding:6px 0;transition:var(--safe-transition)}
        .main-nav a::after{content:"";position:absolute;left:0;bottom:0;width:0;height:2px;background:var(--safe-primary);transition:var(--safe-transition)}
        .main-nav a:hover::after,.main-nav a.active::after{width:100%}
        .main-nav a.active{color:var(--safe-primary)}
        .menu-button{display:none;background:none;border:none;cursor:pointer;width:32px;height:32px;flex-direction:column;justify-content:center;gap:5px}
        .menu-button span{display:block;width:22px;height:2px;background:var(--safe-text);border-radius:2px;transition:var(--safe-transition)}

        /* 通用按钮样式（确保边框正常） */
        .download-buttons{display:flex;flex-wrap:wrap;gap:14px}
        .download-button{
            display:inline-flex;
            align-items:center;
            justify-content:center;
            gap:8px;
            font-weight:600;
            padding:12px 22px;
            border-radius:50px;
            border:1.5px solid transparent;
            transition:var(--safe-transition);
            box-shadow:0 8px 20px rgba(13,27,42,.15);
            cursor:pointer;
            text-align:center;
        }
        .download-button:hover{
            transform:translateY(-2px);
            box-shadow:0 12px 24px rgba(11,95,255,.25);
        }

        /* 关于页面 Hero 特有 */
        .about-hero{background:var(--about-gradient);color:#fff;padding:80px 0 70px;position:relative;overflow:hidden}
        .about-hero::before{content:"";position:absolute;top:-20%;right:-10%;width:600px;height:600px;background:radial-gradient(circle,rgba(225,29,72,.25) 0%,transparent 70%);border-radius:50%;pointer-events:none}
        .about-hero::after{content:"";position:absolute;bottom:-30%;left:-10%;width:500px;height:500px;background:radial-gradient(circle,rgba(0,212,170,.15) 0%,transparent 70%);border-radius:50%;pointer-events:none}
        .about-hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:50px;align-items:center;position:relative;z-index:2}
        .about-hero-kicker{display:inline-block;background:rgba(255,255,255,.1);backdrop-filter:blur(8px);color:#fecdd3;font-weight:700;font-size:14px;padding:8px 18px;border-radius:40px;margin-bottom:18px;letter-spacing:.5px}
        .about-hero-heading{font-size:clamp(2.2rem,4.5vw,3.4rem);line-height:1.2;font-weight:800;margin-bottom:20px}
        .about-hero-heading span{color:var(--safe-accent)}
        .about-hero-text{font-size:1.15rem;color:rgba(255,255,255,.85);max-width:560px;margin-bottom:30px}
        .about-hero-media img{border-radius:24px;box-shadow:0 30px 60px rgba(0,0,0,.3)}

        /* 品牌故事时间线 */
        .story-section{padding:90px 0;background:var(--safe-bg)}
        .story-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .story-timeline{position:relative;max-width:900px;margin:0 auto}
        .story-timeline::before{content:"";position:absolute;left:50%;top:0;bottom:0;width:2px;background:var(--safe-border);transform:translateX(-50%)}
        .story-item{display:flex;justify-content:flex-end;padding:20px 40px 20px 0;position:relative;width:50%}
        .story-item:nth-child(odd){justify-content:flex-start;padding:20px 0 20px 40px;left:50%}
        .story-item .story-content{background:var(--safe-bg-alt);border:1px solid var(--safe-border);border-radius:16px;padding:24px;max-width:380px;transition:var(--safe-transition)}
        .story-item .story-content:hover{box-shadow:var(--safe-shadow)}
        .story-item .story-dot{position:absolute;top:30px;width:16px;height:16px;border-radius:50%;background:var(--about-accent);border:3px solid #fff;box-shadow:0 0 0 3px var(--about-accent-light);z-index:2}
        .story-item:nth-child(odd) .story-dot{left:-8px}
        .story-item:nth-child(even) .story-dot{right:-8px}
        .story-content h3{font-size:1.2rem;font-weight:700;color:var(--safe-dark);margin-bottom:8px}
        .story-content p{color:var(--safe-muted);font-size:0.9rem}
        @media(max-width:768px){
            .story-timeline::before{left:20px}
            .story-item{width:100%;justify-content:flex-start;padding-left:60px;padding-right:0;left:0}
            .story-item:nth-child(odd){left:0;padding-left:60px;padding-right:0}
            .story-item .story-dot{left:12px!important;right:auto!important}
        }

        /* 隐私保护理念 - 价值观光谱 */
        .values-section{padding:90px 0;background:var(--about-soft-bg)}
        .values-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:20px}
        .values-subtitle{text-align:center;color:var(--safe-muted);max-width:700px;margin:0 auto 50px;font-size:1.05rem}
        .values-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:28px}
        .value-card{background:#fff;border-radius:var(--safe-radius);padding:32px 24px;text-align:center;border:1px solid var(--safe-border);transition:var(--safe-transition)}
        .value-card:hover{transform:translateY(-6px);box-shadow:var(--safe-shadow);border-color:var(--about-accent)}
        .value-icon{font-size:2.5rem;margin-bottom:16px}
        .value-card h3{font-size:1.3rem;font-weight:700;color:var(--safe-dark);margin-bottom:10px}
        .value-card p{color:var(--safe-muted);font-size:.95rem}

        /* 与传统通讯工具对比 */
        .comparison-section{padding:90px 0;background:var(--safe-bg)}
        .comparison-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .comparison-grid{display:grid;grid-template-columns:1fr 1fr;gap:30px;max-width:1000px;margin:0 auto}
        .comparison-card{background:var(--safe-bg-alt);border-radius:var(--safe-radius);padding:36px 28px;border:1px solid var(--safe-border)}
        .comparison-card.safe{background:linear-gradient(145deg,#f0f6ff 0%,#ffffff 100%);border-color:var(--safe-primary)}
        .comparison-card.traditional{background:linear-gradient(145deg,#fef2f2 0%,#ffffff 100%);border-color:#fca5a5}
        .comparison-card h3{font-size:1.6rem;font-weight:700;margin-bottom:20px;text-align:center}
        .comparison-card.safe h3{color:var(--safe-primary)}
        .comparison-card.traditional h3{color:var(--about-accent)}
        .comparison-list{list-style:none}
        .comparison-list li{display:flex;gap:10px;align-items:flex-start;margin-bottom:14px;color:var(--safe-text);font-weight:500}
        .comparison-list li::before{content:"✓";color:var(--safe-accent);font-weight:800;flex-shrink:0;margin-top:2px}
        .comparison-list li.cross::before{content:"✕";color:var(--about-accent);font-weight:800}

        /* 安全技术栈 */
        .tech-section{padding:90px 0;background:var(--safe-bg-alt)}
        .tech-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .tech-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:24px;max-width:1000px;margin:0 auto}
        .tech-item{background:#fff;border-radius:16px;padding:28px 20px;text-align:center;border:1px solid var(--safe-border);transition:var(--safe-transition)}
        .tech-item:hover{transform:translateY(-5px);box-shadow:var(--safe-shadow)}
        .tech-icon{font-size:2.5rem;margin-bottom:12px}
        .tech-item h3{font-size:1.2rem;font-weight:700;color:var(--safe-dark);margin-bottom:8px}
        .tech-item p{color:var(--safe-muted);font-size:.9rem}

        /* 数据与隐私承诺 */
        .promise-section{padding:90px 0;background:var(--safe-bg)}
        .promise-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .stat-grid{display:flex;flex-wrap:wrap;justify-content:space-around;gap:20px}
        .stat-item{text-align:center;min-width:150px}
        .stat-number{font-size:2.5rem;font-weight:800;color:var(--about-accent);line-height:1.2}
        .stat-label{color:var(--safe-muted);font-weight:600;font-size:0.95rem;margin-top:4px}

        /* 引述/愿景 */
        .vision-section{padding:90px 0;background:var(--about-soft-bg)}
        .vision-card{max-width:800px;margin:0 auto;background:#fff;border-radius:24px;padding:48px 32px;text-align:center;box-shadow:var(--safe-shadow)}
        .vision-icon{font-size:3rem;margin-bottom:20px}
        .vision-quote{font-size:1.6rem;font-weight:700;color:var(--safe-dark);line-height:1.4;margin-bottom:16px}
        .vision-author{color:var(--safe-muted);font-weight:600}

        /* 底部行动号召 */
        .cta-section{padding:90px 0;background:var(--about-gradient);color:#fff}
        .cta-grid{display:grid;grid-template-columns:1fr 1fr;gap:50px;align-items:center}
        .cta-copy h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;margin-bottom:26px}
        .cta-copy .download-buttons{display:flex;flex-wrap:wrap;gap:14px}
        .cta-copy .download-button{display:inline-flex;align-items:center;gap:8px;background:#fff;color:var(--safe-dark);font-weight:600;padding:12px 22px;border-radius:50px;transition:var(--safe-transition);box-shadow:0 10px 30px rgba(0,0,0,.3)}
        .cta-copy .download-button:hover{background:var(--safe-accent);color:var(--safe-dark);transform:translateY(-2px)}
        .cta-media img{border-radius:24px;box-shadow:0 30px 60px rgba(0,0,0,.3)}

        /* Footer (与首页一致) */
        .site-footer{background:var(--safe-darker);color:#aebdce;padding:60px 0 20px}
        .footer-wrap{max-width:1200px;margin:0 auto;padding:0 24px}
        .footer-logo{display:flex;align-items:center;gap:8px;font-weight:800;font-size:1.5rem;color:#fff;margin-bottom:32px;}
        .footer-logo img{height:40px;margin-bottom:0;}
        .footer-cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:32px;margin-bottom:40px}
        .footer-cols h2{font-size:1.1rem;font-weight:700;color:#fff;margin-bottom:16px}
        .footer-cols p{display:flex;flex-direction:column;gap:8px}
        .footer-cols a{color:#aebdce;transition:var(--safe-transition)}
        .footer-cols a:hover{color:var(--safe-primary)}
        .footer-cols .mail-link{color:var(--safe-accent)}
        .site-footer small{display:block;text-align:center;padding-top:20px;border-top:1px solid rgba(255,255,255,.08);color:#64748b;font-size:.85rem}

        /* Responsive */
        @media(max-width:900px){
            .about-hero-grid,.cta-grid,.comparison-grid{grid-template-columns:1fr;text-align:center}
            .about-hero-text{margin-left:auto;margin-right:auto}
            .download-buttons{justify-content:center}
            .about-hero-media img{margin:0 auto}
        }
        @media(max-width:768px){
            .main-nav{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;flex-direction:column;padding:20px;box-shadow:0 20px 40px rgba(0,0,0,.08);border-bottom:1px solid var(--safe-border);gap:12px}
            .main-nav.open{display:flex}
            .menu-button{display:flex}
            .nav-shell{flex-wrap:wrap}
        }