:root {
    --blue: #2980FE;
    --blue-hover: #1768E8;
    --purple: #7B4EF1;
    --pink: #B84DDA;
    --navy: #101B3D;
    --text: #233047;
    --muted: #68758A;
    --line: #E4EAF3;
    --soft: #F5F8FC;
    --soft-blue: #EEF5FF;
    --white: #FFFFFF;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --shadow: 0 18px 45px rgba(36, 54, 92, 0.10);
    --radius: 24px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
    color: var(--text);
    background: #fff;
    line-height: 1.75;
    overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.container {
    width: min(1120px, calc(100% - 32px));
    margin: 0 auto;
}
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255,255,255,0.94);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(226,233,243,0.9);
}
.nav-wrap {
    min-height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}
.logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; color: var(--navy); font-size: 20px; }
.logo img { width: 40px; height: 40px; border-radius: 12px; object-fit: cover; box-shadow: 0 8px 20px rgba(41,128,254,0.18); }
.nav-toggle { display: none; }
.nav-toggle-label { width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 14px; display: grid; place-content: center; gap: 5px; cursor: pointer; }
.nav-toggle-label span { display: block; width: 18px; height: 2px; background: var(--navy); border-radius: 99px; }
.site-nav { display: none; position: absolute; top: 68px; left: 16px; right: 16px; background: #fff; border: 1px solid var(--line); border-radius: 20px; padding: 14px; box-shadow: var(--shadow); }
.site-nav a { display: block; padding: 12px 14px; color: var(--muted); border-radius: 12px; font-weight: 650; }
.site-nav a.active, .site-nav a:hover { color: var(--blue); background: var(--soft-blue); }
.nav-toggle:checked ~ .site-nav { display: block; }
.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 28px;
    border-radius: 999px;
    background: var(--blue);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 16px 32px rgba(41,128,254,0.28);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}
.download-btn:hover { background: var(--blue-hover); transform: translateY(-2px); box-shadow: 0 18px 36px rgba(23,104,232,0.32); }
.text-link { color: var(--blue); font-weight: 750; display: inline-flex; align-items: center; gap: 6px; }
.text-link::after { content: "→"; }
.section { padding: 64px 0; }
.section.alt { background: var(--soft); }
.section-head { max-width: 720px; margin: 0 auto 30px; text-align: center; }
.eyebrow, .page-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--blue);
    background: rgba(41,128,254,0.10);
    border: 1px solid rgba(41,128,254,0.16);
    border-radius: 999px;
    padding: 6px 12px;
    font-size: 13px;
    font-weight: 800;
}
h1, h2, h3 { color: var(--navy); line-height: 1.22; margin: 0 0 16px; }
h1 { font-size: clamp(34px, 8vw, 62px); letter-spacing: -1.6px; }
h2 { font-size: clamp(28px, 5vw, 42px); letter-spacing: -1px; }
h3 { font-size: 20px; }
p { margin: 0 0 16px; color: var(--muted); }
ul, ol { color: var(--muted); margin: 0; padding-left: 20px; }
.vpn-network-hero {
    position: relative;
    overflow: hidden;
    background: var(--gradient);
    color: #fff;
    padding: 72px 0 40px;
}
.vpn-network-hero::before, .vpn-network-hero::after {
    content: "";
    position: absolute;
    inset: auto;
    border-radius: 50%;
    filter: blur(2px);
    opacity: .42;
}
.vpn-network-hero::before { width: 420px; height: 420px; right: -120px; top: -120px; background: rgba(255,255,255,.22); }
.vpn-network-hero::after { width: 280px; height: 280px; left: -70px; bottom: -80px; background: rgba(255,255,255,.18); }
.network-lines {
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(circle at 18% 28%, rgba(255,255,255,.55) 0 2px, transparent 3px),
        radial-gradient(circle at 76% 34%, rgba(255,255,255,.45) 0 2px, transparent 3px),
        radial-gradient(circle at 62% 72%, rgba(255,255,255,.38) 0 2px, transparent 3px),
        linear-gradient(115deg, transparent 0 20%, rgba(255,255,255,.12) 20.2% 20.6%, transparent 21%),
        linear-gradient(38deg, transparent 0 46%, rgba(255,255,255,.14) 46.2% 46.6%, transparent 47%);
    opacity: .75;
}
.hero-grid { position: relative; z-index: 1; display: grid; gap: 34px; align-items: center; }
.hero-copy h1, .hero-copy p { color: #fff; }
.hero-copy p { font-size: 18px; opacity: .92; max-width: 620px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0 28px; }
.hero-tags span, .status-chip {
    display: inline-flex;
    align-items: center;
    border: 1px solid rgba(255,255,255,.32);
    background: rgba(255,255,255,.15);
    color: #fff;
    border-radius: 999px;
    padding: 8px 12px;
    font-size: 13px;
    font-weight: 750;
}
.hero-visual { position: relative; min-height: 360px; display: grid; place-items: center; }
.hero-device {
    width: min(420px, 88vw);
    padding: 20px;
    border-radius: 34px;
    background: rgba(255,255,255,.16);
    border: 1px solid rgba(255,255,255,.30);
    box-shadow: 0 30px 70px rgba(9, 19, 54, .23);
    backdrop-filter: blur(16px);
}
.hero-device img { border-radius: 26px; }
.float-card {
    position: absolute;
    color: var(--navy);
    background: rgba(255,255,255,.92);
    border: 1px solid rgba(255,255,255,.6);
    border-radius: 16px;
    padding: 10px 14px;
    box-shadow: 0 18px 38px rgba(16,27,61,.18);
    font-weight: 800;
    font-size: 13px;
}
.float-card.one { top: 22px; left: 2%; }
.float-card.two { top: 74px; right: 0; }
.float-card.three { bottom: 70px; left: 0; }
.float-card.four { bottom: 22px; right: 7%; }
.node-overview { margin-top: -36px; position: relative; z-index: 3; }
.node-overview-grid, .card-grid, .risk-grid, .faq-grid, .process-steps, .policy-grid { display: grid; gap: 18px; }
.node-card, .info-card, .risk-card, .faq-item, .step-card, .policy-card, .safety-panel, .side-panel {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: 0 12px 34px rgba(48,67,102,.07);
}
.node-card .tag { display: inline-block; color: var(--blue); background: var(--soft-blue); border-radius: 999px; padding: 4px 10px; font-size: 12px; font-weight: 800; margin-bottom: 12px; }
.service-split, .privacy-grid, .device-grid, .protocol-grid, .download-grid, .about-grid, .page-grid { display: grid; gap: 28px; align-items: center; }
.visual-card { border-radius: 32px; background: #fff; border: 1px solid var(--line); padding: 18px; box-shadow: var(--shadow); }
.visual-card img { border-radius: 24px; }
.feature-list { display: grid; gap: 12px; margin: 18px 0; padding: 0; list-style: none; }
.feature-list li { color: var(--text); background: var(--soft); border: 1px solid var(--line); border-radius: 16px; padding: 12px 14px; }
.global-nodes-section { position: relative; overflow: hidden; background: linear-gradient(180deg, #F7FAFF 0%, #FFFFFF 100%); }
.map-panel {
    position: relative;
    min-height: 340px;
    border-radius: 32px;
    overflow: hidden;
    background: radial-gradient(circle at 30% 30%, rgba(41,128,254,.22), transparent 30%), radial-gradient(circle at 72% 62%, rgba(123,78,241,.20), transparent 28%), #fff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
    display: grid;
    place-items: center;
}
.map-panel::before {
    content: "";
    position: absolute;
    inset: 28px;
    border-radius: 26px;
    background-image: linear-gradient(90deg, rgba(41,128,254,.10) 1px, transparent 1px), linear-gradient(0deg, rgba(41,128,254,.10) 1px, transparent 1px);
    background-size: 34px 34px;
}
.map-panel img { position: relative; z-index: 1; width: min(420px, 82%); border-radius: 24px; }
.node-dot { position: absolute; z-index: 2; width: 12px; height: 12px; border-radius: 50%; background: var(--blue); box-shadow: 0 0 0 8px rgba(41,128,254,.14); }
.node-dot.a { left: 18%; top: 34%; }
.node-dot.b { right: 24%; top: 28%; }
.node-dot.c { left: 44%; bottom: 25%; }
.node-dot.d { right: 18%; bottom: 32%; }
.speed-panel { background: #fff; border: 1px solid var(--line); border-radius: 32px; padding: 24px; box-shadow: var(--shadow); }
.speed-line { display: flex; justify-content: space-between; gap: 16px; padding: 14px 0; border-bottom: 1px solid var(--line); color: var(--muted); }
.speed-line:last-child { border-bottom: 0; }
.speed-line strong { color: var(--navy); }
.privacy-protection-section .safety-panel { background: linear-gradient(180deg, #fff 0%, #F8FBFF 100%); }
.security-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }
.security-tags span { color: var(--blue); background: var(--soft-blue); border: 1px solid rgba(41,128,254,.14); border-radius: 999px; padding: 8px 12px; font-weight: 750; font-size: 13px; }
.protocol-panel { background: var(--navy); color: #fff; border-radius: 32px; padding: 26px; box-shadow: var(--shadow); }
.protocol-panel h3, .protocol-panel p { color: #fff; }
.protocol-stack { display: grid; gap: 12px; margin-top: 18px; }
.protocol-stack div { background: rgba(255,255,255,.10); border: 1px solid rgba(255,255,255,.18); border-radius: 18px; padding: 14px; }
.step-card { position: relative; }
.step-no { width: 38px; height: 38px; border-radius: 14px; display: grid; place-items: center; color: #fff; background: var(--blue); font-weight: 900; margin-bottom: 14px; }
.risk-card { border-left: 4px solid var(--blue); }
.cta-section { padding: 58px 0; background: var(--gradient); color: #fff; text-align: center; position: relative; overflow: hidden; }
.cta-section h2, .cta-section p { color: #fff; }
.cta-inner { max-width: 760px; margin: 0 auto; position: relative; z-index: 1; }
.page-hero { padding: 58px 0 34px; background: linear-gradient(180deg, #F6F9FF 0%, #fff 100%); }
.page-hero .container { max-width: 900px; }
.page-hero h1 { font-size: clamp(32px, 6vw, 52px); }
.page-layout { padding: 42px 0 68px; }
.article-card { background: #fff; border: 1px solid var(--line); border-radius: 30px; padding: 26px; box-shadow: var(--shadow); }
.article-card h2 { font-size: 28px; }
.tip-box { background: var(--soft-blue); border: 1px solid rgba(41,128,254,.16); border-radius: 22px; padding: 20px; margin: 20px 0; }
.check-list { display: grid; gap: 12px; padding: 0; list-style: none; }
.check-list li { padding: 12px 14px; background: var(--soft); border: 1px solid var(--line); border-radius: 14px; color: var(--text); }
.check-list li::before { content: "✓"; color: var(--blue); font-weight: 900; margin-right: 8px; }
.side-panel { align-self: start; }
.side-panel a { display: block; color: var(--blue); font-weight: 750; padding: 10px 0; border-bottom: 1px solid var(--line); }
.side-panel a:last-child { border-bottom: 0; }
.download-card { max-width: 760px; margin: 0 auto; text-align: center; }
.download-steps { counter-reset: step; display: grid; gap: 16px; margin-top: 28px; text-align: left; }
.download-steps li { list-style: none; background: #fff; border: 1px solid var(--line); border-radius: 18px; padding: 16px; box-shadow: 0 10px 26px rgba(48,67,102,.06); }
.faq-item h3 { font-size: 18px; margin-bottom: 8px; }
.site-footer { background: #0F1833; color: rgba(255,255,255,.78); padding: 48px 0 24px; }
.footer-grid { display: grid; gap: 28px; }
.footer-brand { color: #fff; font-weight: 900; font-size: 24px; margin-bottom: 10px; }
.site-footer h3 { color: #fff; font-size: 16px; margin-bottom: 12px; }
.site-footer a { display: block; color: rgba(255,255,255,.74); margin: 8px 0; }
.footer-bottom { margin-top: 28px; padding-top: 20px; border-top: 1px solid rgba(255,255,255,.12); display: flex; flex-direction: column; gap: 8px; color: rgba(255,255,255,.62); font-size: 14px; }
@media (min-width: 640px) {
    .node-overview-grid, .card-grid, .policy-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .risk-grid, .faq-grid, .process-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (min-width: 900px) {
    .nav-toggle-label { display: none; }
    .site-nav { display: flex; position: static; align-items: center; gap: 4px; padding: 0; border: 0; box-shadow: none; background: transparent; }
    .site-nav a { padding: 8px 10px; font-size: 14px; }
    .hero-grid, .service-split, .privacy-grid, .device-grid, .protocol-grid, .download-grid, .about-grid, .page-grid { grid-template-columns: 1.05fr .95fr; }
    .node-overview-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
    .card-grid.three, .risk-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .footer-grid { grid-template-columns: 1.4fr repeat(3, 1fr); }
    .footer-bottom { flex-direction: row; justify-content: space-between; align-items: center; }
    .vpn-network-hero { padding: 92px 0 74px; }
    .section { padding: 84px 0; }
}
@media (max-width: 420px) {
    .container { width: min(100% - 24px, 1120px); }
    .download-btn { width: 100%; }
    .hero-visual { min-height: 320px; }
    .float-card { font-size: 12px; padding: 8px 10px; }
    .article-card, .node-card, .info-card, .risk-card, .faq-item, .step-card, .policy-card, .safety-panel, .side-panel { padding: 20px; border-radius: 20px; }
}