/* =========================================================
       设计令牌（Design Tokens）— 深色主题锁定，单一翠绿强调色
       ========================================================= */
    :root {
        --bg:            #070b0a;
        --bg-2:          #0a0f0d;
        --surface:       rgba(255, 255, 255, .028);
        --surface-2:     rgba(255, 255, 255, .045);
        --line:          rgba(255, 255, 255, .08);
        --line-strong:   rgba(255, 255, 255, .14);

        --ink:           #eef3f0;
        --muted:         #9aa9a2;
        --muted-2:       #6d7c75;

        --accent:        #35d99a;   /* 翠绿：连接/安全/自由 */
        --accent-soft:   #58e2ac;
        --accent-strong: #10b981;
        --accent-glow:   rgba(53, 217, 154, .35);
        --on-accent:     #04140d;

        /* 单一圆角体系：卡片 16、图标框 12、按钮胶囊 */
        --r-card: 16px;
        --r-tile: 12px;
        --r-pill: 999px;

        --maxw: 1200px;
        --nav-h: 68px;

        --sans: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei",
                "Hiragino Sans GB", "Noto Sans CJK SC", "Source Han Sans SC", sans-serif;
        --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;

        --ease: cubic-bezier(.16, 1, .3, 1);
    }

    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }

    body {
        margin: 0;
        font-family: var(--sans);
        color: var(--ink);
        background: var(--bg);
        line-height: 1.6;
        -webkit-font-smoothing: antialiased;
        text-rendering: optimizeLegibility;
        overflow-x: hidden;
    }
    a { color: inherit; text-decoration: none; }
    img, svg { max-width: 100%; display: block; }
    h1, h2, h3 { margin: 0; font-weight: 700; line-height: 1.15; letter-spacing: -.01em; }
    p { margin: 0; }

    .wrap { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

    /* 背景氛围光 */
    body::before {
        content: "";
        position: fixed;
        inset: 0;
        z-index: -2;
        background:
            radial-gradient(720px 480px at 78% -6%, rgba(53,217,154,.16), transparent 60%),
            radial-gradient(680px 520px at 8% 8%,   rgba(16,185,129,.10), transparent 62%),
            linear-gradient(180deg, var(--bg), var(--bg-2) 60%, var(--bg));
        pointer-events: none;
    }
    /* 细颗粒噪点（固定层，不随滚动重绘） */
    .grain {
        position: fixed; inset: 0; z-index: 60; pointer-events: none; opacity: .04;
        background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
    }

    /* =========================================================
       导航
       ========================================================= */
    .nav {
        position: fixed; top: 0; left: 0; right: 0; z-index: 50;
        height: var(--nav-h);
        display: flex; align-items: center;
        transition: background .35s var(--ease), border-color .35s var(--ease), backdrop-filter .35s var(--ease);
        border-bottom: 1px solid transparent;
    }
    .nav.scrolled {
        background: rgba(8, 12, 11, .72);
        backdrop-filter: saturate(160%) blur(14px);
        -webkit-backdrop-filter: saturate(160%) blur(14px);
        border-bottom-color: var(--line);
    }
    .nav .wrap { display: flex; align-items: center; justify-content: space-between; }
    .brand { display: flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: -.02em; font-size: 18px; }
    .brand .dot {
        width: 26px; height: 26px; border-radius: 8px;
        background: linear-gradient(140deg, var(--accent), var(--accent-strong));
        display: grid; place-items: center; color: var(--on-accent);
        box-shadow: 0 0 0 1px rgba(255,255,255,.12) inset, 0 8px 22px -8px var(--accent-glow);
    }
    .brand .dot svg { width: 15px; height: 15px; }

    .nav-links { display: flex; align-items: center; gap: 4px; }
    .nav-links a {
        color: var(--muted); font-size: 14.5px; font-weight: 500;
        padding: 8px 14px; border-radius: var(--r-pill);
        transition: color .2s var(--ease), background .2s var(--ease);
    }
    .nav-links a:hover { color: var(--ink); background: var(--surface); }

    .nav-cta { display: flex; align-items: center; gap: 10px; }

    .btn {
        display: inline-flex; align-items: center; justify-content: center; gap: 9px;
        font-family: var(--sans); font-weight: 600; font-size: 15px; white-space: nowrap;
        border: 1px solid transparent; border-radius: var(--r-pill); cursor: pointer;
        padding: 12px 22px; transition: transform .18s var(--ease), background .2s var(--ease),
            border-color .2s var(--ease), box-shadow .2s var(--ease); text-align: center;
    }
    .btn svg { width: 18px; height: 18px; }
    .btn:active { transform: translateY(1px) scale(.99); }
    .btn-primary {
        background: linear-gradient(140deg, var(--accent-soft), var(--accent-strong));
        color: var(--on-accent);
        box-shadow: 0 10px 30px -12px var(--accent-glow), inset 0 1px 0 rgba(255,255,255,.28);
    }
    .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 18px 42px -14px var(--accent-glow), inset 0 1px 0 rgba(255,255,255,.3); }
    .btn-ghost { background: var(--surface); color: var(--ink); border-color: var(--line-strong); }
    .btn-ghost:hover { transform: translateY(-2px); background: var(--surface-2); border-color: rgba(255,255,255,.24); }
    .btn-sm { padding: 9px 18px; font-size: 14px; }

    .nav-toggle {
        display: none; width: 42px; height: 42px; border-radius: 11px;
        background: var(--surface); border: 1px solid var(--line-strong);
        color: var(--ink); cursor: pointer; place-items: center;
    }
    .nav-toggle svg { width: 20px; height: 20px; }

    /* =========================================================
       Hero — 非对称分栏
       ========================================================= */
    .hero { position: relative; padding-top: calc(var(--nav-h) + 40px); padding-bottom: 40px; min-height: 100dvh; display: flex; align-items: center; }
    .hero-grid {
        display: grid; grid-template-columns: 1.05fr .95fr; gap: 48px; align-items: center; width: 100%;
    }
    .chip {
        display: inline-flex; align-items: center; gap: 8px;
        padding: 7px 14px; border-radius: var(--r-pill);
        background: rgba(53,217,154,.08); border: 1px solid rgba(53,217,154,.24);
        color: var(--accent-soft); font-size: 13px; font-weight: 600; letter-spacing: .01em;
    }
    .chip .pulse {
        width: 7px; height: 7px; border-radius: 50%; background: var(--accent);
        box-shadow: 0 0 0 0 var(--accent-glow); animation: pulse 2.4s var(--ease) infinite;
    }
    @keyframes pulse {
        0% { box-shadow: 0 0 0 0 rgba(53,217,154,.5); }
        70% { box-shadow: 0 0 0 9px rgba(53,217,154,0); }
        100% { box-shadow: 0 0 0 0 rgba(53,217,154,0); }
    }

    .hero h1 {
        font-size: clamp(38px, 6vw, 66px);
        letter-spacing: -.02em; line-height: 1.08; margin: 22px 0 0;
    }
    .hero h1 .glow { color: var(--accent); text-shadow: 0 0 34px var(--accent-glow); }
    .hero-sub {
        margin-top: 22px; color: var(--muted); font-size: clamp(16px, 2vw, 19px);
        max-width: 30ch;
    }
    .hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 34px; }
    .hero-actions .btn { padding: 15px 26px; font-size: 16px; }

    /* Hero 视觉：抽象「安全全球连接」几何图 */
    .hero-visual { position: relative; display: grid; place-items: center; }
    .globe-wrap { width: min(100%, 480px); aspect-ratio: 1; position: relative; }
    .globe-wrap svg { width: 100%; height: 100%; overflow: visible; }
    .float { animation: float 7s ease-in-out infinite; transform-box: fill-box; transform-origin: center; }
    @keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-14px); } }
    .spin-slow { animation: spin 34s linear infinite; transform-box: fill-box; transform-origin: center; }
    .spin-rev  { animation: spin 46s linear infinite reverse; transform-box: fill-box; transform-origin: center; }
    @keyframes spin { to { transform: rotate(360deg); } }
    .flow { stroke-dasharray: 6 10; animation: flow 1.6s linear infinite; }
    @keyframes flow { to { stroke-dashoffset: -32; } }
    .twinkle { animation: twinkle 3s ease-in-out infinite; }
    .twinkle.b { animation-delay: .8s; }
    .twinkle.c { animation-delay: 1.6s; }
    @keyframes twinkle { 0%,100% { opacity: .35; } 50% { opacity: 1; } }

    /* =========================================================
       通用区块
       ========================================================= */
    section { position: relative; }
    .section-pad { padding: clamp(72px, 10vw, 128px) 0; }
    .sec-head { max-width: 620px; }
    .eyebrow {
        display: inline-block; font-size: 12px; font-weight: 700; letter-spacing: .18em;
        text-transform: uppercase; color: var(--accent); margin-bottom: 14px;
    }
    .sec-head h2 { font-size: clamp(28px, 4.4vw, 44px); letter-spacing: -.02em; }
    .sec-head p { margin-top: 16px; color: var(--muted); font-size: 17px; max-width: 54ch; }

    /* 揭示动画 */
    .reveal { opacity: 0; transform: translateY(26px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
    html.js .reveal.is-in { opacity: 1; transform: none; }

    /* =========================================================
       特性 — Bento（有节奏、非等分）
       ========================================================= */
    .bento { display: grid; grid-template-columns: repeat(6, 1fr); gap: 16px; margin-top: 48px; }
    .cell {
        position: relative; overflow: hidden;
        background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-card);
        padding: 28px; transition: border-color .3s var(--ease), transform .3s var(--ease), background .3s var(--ease);
    }
    .cell:hover { border-color: var(--line-strong); transform: translateY(-3px); background: var(--surface-2); }
    .cell.wide  { grid-column: span 3; }
    .cell.small { grid-column: span 2; }
    .cell.full  { grid-column: span 6; }
    .cell.feature { background:
        radial-gradient(420px 220px at 88% 0%, rgba(53,217,154,.14), transparent 62%), var(--surface); }
    .cell.feature.b { background:
        radial-gradient(420px 240px at 12% 110%, rgba(16,185,129,.16), transparent 60%), var(--surface); }
    .icon {
        width: 46px; height: 46px; border-radius: var(--r-tile); display: grid; place-items: center;
        background: rgba(53,217,154,.1); border: 1px solid rgba(53,217,154,.22); color: var(--accent-soft);
        margin-bottom: 18px;
    }
    .icon svg { width: 23px; height: 23px; stroke-width: 1.75; }
    .cell h3 { font-size: 20px; }
    .cell p { margin-top: 9px; color: var(--muted); font-size: 15px; }
    .cell.full { display: flex; align-items: center; gap: 24px; padding: 26px 30px; }
    .cell.full .icon { margin-bottom: 0; flex: 0 0 auto; }
    .cell.full .txt h3 { font-size: 19px; }

    /* 迷你速度条（特性视觉变化） */
    .speedbars { display: flex; align-items: flex-end; gap: 6px; height: 42px; margin-top: 20px; }
    .speedbars i { width: 12px; border-radius: 4px; background: linear-gradient(180deg, var(--accent-soft), var(--accent-strong)); opacity: .85; animation: eq 1.4s var(--ease) infinite; }
    .speedbars i:nth-child(1){height:40%;animation-delay:0s}
    .speedbars i:nth-child(2){height:70%;animation-delay:.15s}
    .speedbars i:nth-child(3){height:100%;animation-delay:.3s}
    .speedbars i:nth-child(4){height:55%;animation-delay:.45s}
    .speedbars i:nth-child(5){height:82%;animation-delay:.6s}
    @keyframes eq { 0%,100%{transform:scaleY(.55)} 50%{transform:scaleY(1)} }

    /* =========================================================
       使用步骤
       ========================================================= */
    .steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 52px; position: relative; }
    .steps::before {
        content: ""; position: absolute; top: 34px; left: 12%; right: 12%; height: 1px;
        background: linear-gradient(90deg, transparent, var(--line-strong), transparent);
    }
    .step { position: relative; }
    .step .num {
        font-family: var(--mono); font-size: 15px; font-weight: 700; color: var(--on-accent);
        width: 56px; height: 56px; border-radius: 50%; display: grid; place-items: center;
        background: linear-gradient(140deg, var(--accent-soft), var(--accent-strong));
        box-shadow: 0 10px 30px -12px var(--accent-glow); position: relative; z-index: 1;
    }
    .step h3 { font-size: 21px; margin-top: 22px; }
    .step p { margin-top: 8px; color: var(--muted); font-size: 15px; max-width: 30ch; }

    /* =========================================================
       隐私宣言（居中陈述）
       ========================================================= */
    .manifesto { text-align: center; }
    .manifesto .wrap { max-width: 900px; }
    .manifesto h2 { font-size: clamp(30px, 5vw, 54px); letter-spacing: -.02em; line-height: 1.15; }
    .manifesto h2 em { font-style: normal; color: var(--accent); text-shadow: 0 0 32px var(--accent-glow); }
    .manifesto p { margin: 22px auto 0; color: var(--muted); font-size: 18px; max-width: 52ch; }

    /* =========================================================
       下载
       ========================================================= */
    .dl-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 48px; }
    .dl-card {
        position: relative; overflow: hidden;
        background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-card);
        padding: 34px; transition: border-color .3s var(--ease), transform .3s var(--ease), background .3s var(--ease);
        display: flex; flex-direction: column; gap: 18px;
    }
    .dl-card:hover { border-color: var(--line-strong); transform: translateY(-4px); background: var(--surface-2); }
    .dl-card::after {
        content: ""; position: absolute; inset: 0; z-index: -1;
        background: radial-gradient(360px 200px at 100% 0%, rgba(53,217,154,.1), transparent 60%);
    }
    .dl-top { display: flex; align-items: center; gap: 16px; }
    .dl-logo { width: 54px; height: 54px; border-radius: 14px; background: var(--surface-2); border: 1px solid var(--line-strong); display: grid; place-items: center; color: var(--ink); }
    .dl-logo svg { width: 30px; height: 30px; }
    .dl-top h3 { font-size: 22px; }
    .dl-top span { color: var(--muted-2); font-size: 14px; }
    .dl-card .btn { margin-top: auto; width: 100%; padding: 14px; }
    .dl-contact { margin-top: 26px; text-align: center; color: var(--muted); font-size: 15px; }
    .dl-contact a { color: var(--accent-soft); font-weight: 600; }
    .dl-contact a:hover { text-decoration: underline; }

    /* =========================================================
       FAQ
       ========================================================= */
    .faq { max-width: 800px; margin: 44px auto 0; }
    .faq details {
        border: 1px solid var(--line); border-radius: var(--r-card); background: var(--surface);
        padding: 0 24px; margin-bottom: 12px; transition: border-color .25s var(--ease), background .25s var(--ease);
    }
    .faq details[open] { border-color: rgba(53,217,154,.3); background: var(--surface-2); }
    .faq summary {
        list-style: none; cursor: pointer; padding: 20px 0; font-size: 17px; font-weight: 600;
        display: flex; align-items: center; justify-content: space-between; gap: 16px;
    }
    .faq summary::-webkit-details-marker { display: none; }
    .faq summary .plus { flex: 0 0 auto; width: 22px; height: 22px; position: relative; transition: transform .3s var(--ease); color: var(--accent); }
    .faq summary .plus::before, .faq summary .plus::after {
        content: ""; position: absolute; background: currentColor; border-radius: 2px;
        top: 50%; left: 50%; transform: translate(-50%,-50%);
    }
    .faq summary .plus::before { width: 14px; height: 2px; }
    .faq summary .plus::after  { width: 2px; height: 14px; transition: transform .3s var(--ease); }
    .faq details[open] summary .plus::after { transform: translate(-50%,-50%) scaleY(0); }
    .faq details p { color: var(--muted); font-size: 15.5px; padding: 0 0 22px; max-width: 62ch; }
    .faq details p a { color: var(--accent-soft); font-weight: 600; }

    /* =========================================================
       结尾 CTA + 页脚
       ========================================================= */
    .final { text-align: center; }
    .final-card {
        position: relative; overflow: hidden; border-radius: 28px;
        border: 1px solid rgba(53,217,154,.25);
        background:
            radial-gradient(560px 300px at 50% -20%, rgba(53,217,154,.2), transparent 65%),
            var(--surface);
        padding: clamp(48px, 8vw, 92px) 24px;
    }
    .final-card h2 { font-size: clamp(28px, 4.6vw, 48px); }
    .final-card p { margin: 16px auto 0; color: var(--muted); max-width: 46ch; font-size: 17px; }
    .final-card .btn { margin-top: 32px; padding: 16px 34px; font-size: 16px; }

    footer { border-top: 1px solid var(--line); padding: 44px 0 40px; margin-top: 0; }
    .foot-grid { display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
    .foot-links { display: flex; gap: 22px; flex-wrap: wrap; }
    .foot-links a { color: var(--muted); font-size: 14.5px; transition: color .2s var(--ease); }
    .foot-links a:hover { color: var(--ink); }
    .copy { color: var(--muted-2); font-size: 13.5px; margin-top: 22px; }
    .copy a { color: var(--muted); transition: color .2s var(--ease); }
    .copy a:hover { color: var(--ink); }

    /* =========================================================
       数据规模条
       ========================================================= */
    .stats { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); background: var(--surface); }
    .stats .wrap { display: grid; grid-template-columns: repeat(4, 1fr); padding-left: 0; padding-right: 0; }
    .stat { padding: 44px 24px; text-align: center; border-right: 1px solid var(--line); }
    .stat:last-child { border-right: none; }
    .stat .num { font-family: var(--mono); font-size: clamp(30px, 4vw, 46px); font-weight: 700; letter-spacing: -.02em; line-height: 1; }
    .stat .num b { color: var(--accent); font-weight: 700; }
    .stat .lbl { margin-top: 12px; color: var(--muted); font-size: 14.5px; }

    /* =========================================================
       全球节点
       ========================================================= */
    .nodes-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin-top: 44px; }
    .node {
        background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-card);
        padding: 20px; display: flex; flex-direction: column; gap: 14px;
        transition: border-color .3s var(--ease), transform .3s var(--ease), background .3s var(--ease);
    }
    .node:hover { border-color: var(--line-strong); transform: translateY(-3px); background: var(--surface-2); }
    .node-top { display: flex; align-items: center; gap: 13px; }
    .node-badge {
        width: 42px; height: 32px; border-radius: 9px; flex: 0 0 auto; display: grid; place-items: center;
        font-family: var(--mono); font-weight: 700; font-size: 13px; letter-spacing: .04em;
        background: var(--surface-2); border: 1px solid var(--line-strong); color: var(--accent-soft);
    }
    .node-name { font-weight: 600; font-size: 16px; }
    .node-city { color: var(--muted-2); font-size: 12.5px; margin-top: 1px; }
    .node-meta { display: flex; align-items: center; justify-content: space-between; margin-top: auto; padding-top: 13px; border-top: 1px solid var(--line); }
    .node-count { color: var(--muted); font-size: 13px; font-family: var(--mono); }
    .node-ping { display: inline-flex; align-items: center; gap: 7px; font-size: 13px; color: var(--accent-soft); font-family: var(--mono); }
    .node-ping .live { width: 7px; height: 7px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 8px var(--accent-glow); animation: pulse 2.4s var(--ease) infinite; }
    .node.more { align-items: center; justify-content: center; text-align: center; border-style: dashed; gap: 6px; }
    .node.more .big { font-family: var(--mono); font-size: 26px; font-weight: 700; color: var(--accent-soft); }
    .node.more span { color: var(--muted); font-size: 13.5px; }

    /* 实时吞吐量波形（模拟流量监控） */
    .node-graph {
        position: relative; height: 36px; overflow: hidden; margin-top: -2px;
        -webkit-mask: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
        mask: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
    }
    .node-graph svg {
        position: absolute; inset: 0; height: 100%; width: 200%;
        animation: throughput 7s linear infinite; will-change: transform;
    }
    .ng-area { fill: rgba(53,217,154,.10); }
    .ng-line { fill: none; stroke: var(--accent); stroke-width: 1.5; opacity: .85; vector-effect: non-scaling-stroke; }
    @keyframes throughput { from { transform: translateX(0); } to { transform: translateX(-50%); } }
    /* 每张卡不同速度/相位，看起来各自独立 */
    .nodes-grid .node:nth-child(2) .node-graph svg { animation-duration: 5.5s; animation-delay: -1.5s; }
    .nodes-grid .node:nth-child(3) .node-graph svg { animation-duration: 8s;   animation-delay: -3s; }
    .nodes-grid .node:nth-child(4) .node-graph svg { animation-duration: 6s;   animation-delay: -.8s; }
    .nodes-grid .node:nth-child(5) .node-graph svg { animation-duration: 9s;   animation-delay: -4s; }
    .nodes-grid .node:nth-child(6) .node-graph svg { animation-duration: 5s;   animation-delay: -2.2s; }
    .nodes-grid .node:nth-child(7) .node-graph svg { animation-duration: 7.5s; animation-delay: -1s; }

    /* =========================================================
       自研加密协议
       ========================================================= */
    .tech-grid { display: grid; grid-template-columns: .92fr 1.08fr; gap: 44px; align-items: center; margin-top: 48px; }
    .tech-panel {
        position: relative; overflow: hidden; border: 1px solid rgba(53,217,154,.25); border-radius: 24px;
        padding: 48px 40px; text-align: center;
        background: radial-gradient(440px 340px at 50% 0%, rgba(53,217,154,.15), transparent 62%), var(--surface);
    }
    .tech-core { width: 150px; height: 150px; margin: 0 auto 26px; position: relative; display: grid; place-items: center; }
    .tech-core .ring { position: absolute; inset: 0; border: 1px solid rgba(53,217,154,.3); border-radius: 50%; }
    .tech-core .ring.r2 { inset: 20px; border-color: rgba(53,217,154,.2); }
    .tech-core .ring.r3 { inset: 40px; border-color: rgba(53,217,154,.14); }
    .tech-core .ring.dash { border-style: dashed; animation: spin 20s linear infinite; }
    .tech-core .lock {
        width: 60px; height: 60px; border-radius: 18px; display: grid; place-items: center; color: var(--on-accent);
        background: linear-gradient(140deg, var(--accent-soft), var(--accent-strong)); box-shadow: 0 0 46px var(--accent-glow);
    }
    .tech-core .lock svg { width: 30px; height: 30px; }
    .tech-panel h3 { font-size: 23px; }
    .tech-panel .proto { font-family: var(--mono); color: var(--accent-soft); font-size: 12.5px; margin-top: 8px; letter-spacing: .02em; }
    .tech-badges { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 24px; }
    .tech-badges span {
        font-family: var(--mono); font-size: 12px; padding: 6px 12px; border-radius: var(--r-pill);
        background: rgba(53,217,154,.08); border: 1px solid rgba(53,217,154,.22); color: var(--accent-soft);
    }
    .tech-item { display: flex; gap: 16px; padding: 24px 0; border-bottom: 1px solid var(--line); }
    .tech-item:first-child { padding-top: 0; }
    .tech-item:last-child { border-bottom: none; padding-bottom: 0; }
    .tech-item .icon { margin-bottom: 0; flex: 0 0 auto; }
    .tech-item h4 { font-size: 17.5px; margin: 0; font-weight: 700; }
    .tech-item p { margin-top: 7px; color: var(--muted); font-size: 14.5px; }

    /* =========================================================
       响应式
       ========================================================= */
    @media (max-width: 900px) {
        .stats .wrap { grid-template-columns: 1fr 1fr; }
        .stat:nth-child(2) { border-right: none; }
        .stat:nth-child(1), .stat:nth-child(2) { border-bottom: 1px solid var(--line); }
        .nodes-grid { grid-template-columns: 1fr 1fr; }
        .tech-grid { grid-template-columns: 1fr; gap: 32px; }
        .hero-grid { grid-template-columns: 1fr; gap: 8px; text-align: left; }
        .hero-visual { order: -1; margin-bottom: 4px; }
        .globe-wrap { width: min(74%, 340px); }
        .hero { min-height: auto; padding-top: calc(var(--nav-h) + 48px); padding-bottom: 64px; }
        .bento { grid-template-columns: 1fr 1fr; }
        .cell.wide, .cell.small, .cell.full { grid-column: span 1; }
        .cell.full { flex-direction: column; align-items: flex-start; }
        .steps { grid-template-columns: 1fr; gap: 32px; }
        .steps::before { display: none; }
        .dl-grid { grid-template-columns: 1fr; }
    }
    @media (max-width: 640px) {
        .wrap { padding: 0 18px; }
        .nav-links { display: none; }
        .nav-toggle { display: grid; }
        .nav.menu-open .nav-links {
            display: flex; position: absolute; top: var(--nav-h); left: 0; right: 0;
            flex-direction: column; align-items: stretch; gap: 4px; padding: 12px 18px 18px;
            background: rgba(8,12,11,.96); backdrop-filter: blur(14px); border-bottom: 1px solid var(--line);
        }
        .nav.menu-open .nav-links a { padding: 12px 14px; }
        .nav .btn.hide-sm { display: none; }
        .bento { grid-template-columns: 1fr; }
        .hero-actions .btn { flex: 1; }
        .foot-grid { flex-direction: column; align-items: flex-start; }
        .nodes-grid { grid-template-columns: 1fr; }
        .stat { padding: 26px 14px; }
        .tech-panel { padding: 36px 24px; }
    }

    /* 无障碍：尊重减少动态偏好 */
    @media (prefers-reduced-motion: reduce) {
        html { scroll-behavior: auto; }
        *, *::before, *::after { animation: none !important; transition: none !important; }
        .reveal { opacity: 1 !important; transform: none !important; }
    }
    :focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 6px; }