:root {
    --primary: #2980FE;
    --primary-dark: #1768E8;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --text: #20283A;
    --muted: #637089;
    --light: #F5F7FB;
    --soft: #EEF3FF;
    --border: #E6EAF2;
    --white: #FFFFFF;
    --shadow: 0 18px 50px rgba(33, 50, 97, .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%; height: auto; display: block; }
.container { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }
.section { padding: 64px 0; }
.section.soft { background: var(--light); }
.section-title { margin: 0 0 14px; font-size: clamp(28px, 4vw, 42px); line-height: 1.2; letter-spacing: -.03em; }
.section-lead { color: var(--muted); max-width: 760px; margin: 0 0 28px; }
.badge, .category-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 12px;
    border-radius: 999px;
    color: var(--primary);
    background: #EBF3FF;
    font-weight: 700;
    font-size: 14px;
}
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255,255,255,.92);
    backdrop-filter: blur(14px);
    border-bottom: 1px solid rgba(230,234,242,.85);
}
.header-inner {
    width: min(1180px, calc(100% - 28px));
    margin: 0 auto;
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
}
.logo, .footer-logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: -.02em; }
.logo img, .footer-logo img { width: 36px; height: 36px; border-radius: 10px; object-fit: cover; }
.site-nav { display: flex; align-items: center; gap: 4px; flex-wrap: wrap; justify-content: flex-end; }
.site-nav a { color: #3C465C; padding: 10px 12px; border-radius: 999px; font-size: 14px; font-weight: 600; }
.site-nav a:hover, .site-nav a.active { color: var(--primary); background: #EDF4FF; }
.nav-toggle, .nav-toggle-label { display: none; }
.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 24px;
    border-radius: 999px;
    background: var(--primary);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 12px 26px rgba(41,128,254,.26);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}
.download-btn:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 16px 32px rgba(23,104,232,.28); }
.text-link { color: var(--primary); font-weight: 800; }
.text-link:hover { color: var(--primary-dark); }
.vpn-network-hero {
    position: relative;
    color: #fff;
    overflow: hidden;
    background: var(--gradient);
}
.vpn-network-hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 20% 18%, rgba(255,255,255,.22), transparent 22%),
        radial-gradient(circle at 74% 28%, rgba(255,255,255,.20), transparent 18%),
        linear-gradient(135deg, rgba(255,255,255,.14) 1px, transparent 1px);
    background-size: auto, auto, 42px 42px;
    opacity: .65;
}
.hero-inner {
    position: relative;
    z-index: 1;
    width: min(1180px, calc(100% - 32px));
    margin: 0 auto;
    padding: 72px 0 80px;
    display: grid;
    gap: 34px;
}
.hero-copy h1 { margin: 16px 0 18px; font-size: clamp(36px, 8vw, 68px); line-height: 1.05; letter-spacing: -.05em; }
.hero-copy p { font-size: 17px; max-width: 650px; color: rgba(255,255,255,.88); margin: 0 0 26px; }
.hero-actions { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.hero-note { color: rgba(255,255,255,.84); font-size: 14px; }
.security-tags { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 26px; }
.security-tags span { border: 1px solid rgba(255,255,255,.26); background: rgba(255,255,255,.12); color: #fff; border-radius: 999px; padding: 8px 12px; font-weight: 700; font-size: 14px; }
.hero-visual { position: relative; min-height: 360px; display: grid; place-items: center; }
.hero-device {
    width: min(430px, 90%);
    border-radius: 34px;
    background: rgba(255,255,255,.14);
    padding: 18px;
    box-shadow: 0 30px 90px rgba(0,0,0,.20);
    backdrop-filter: blur(8px);
}
.hero-device img { border-radius: 26px; width: 100%; object-fit: cover; }
.float-card {
    position: absolute;
    background: rgba(255,255,255,.92);
    color: #26324D;
    border: 1px solid rgba(255,255,255,.7);
    border-radius: 18px;
    padding: 10px 14px;
    font-weight: 800;
    box-shadow: 0 18px 38px rgba(21,31,70,.18);
    font-size: 13px;
}
.float-card.one { top: 36px; left: 0; }
.float-card.two { top: 92px; right: 0; }
.float-card.three { bottom: 78px; left: 8px; }
.float-card.four { bottom: 24px; right: 28px; }
.hero-kicker { color: #fff; background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.22); }
.node-overview { margin-top: -34px; position: relative; z-index: 3; }
.node-overview-grid { display: grid; gap: 16px; }
.node-card, .feature-card, .risk-card, .faq-item, .policy-card, .step-card, .article-card, .side-panel, .protocol-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: 0 12px 35px rgba(33,50,97,.07);
}
.node-card { padding: 22px; }
.node-card .tag { color: var(--primary); font-weight: 900; font-size: 13px; }
.node-card h3 { margin: 8px 0 8px; font-size: 20px; }
.node-card p, .feature-card p, .policy-card p, .risk-card p, .step-card p, .protocol-card p { color: var(--muted); margin: 0 0 12px; }
.split-section { display: grid; gap: 28px; align-items: center; }
.image-panel { border-radius: 32px; overflow: hidden; background: var(--soft); box-shadow: var(--shadow); padding: 14px; }
.image-panel img { border-radius: 24px; width: 100%; object-fit: cover; }
.feature-list, .check-list { display: grid; gap: 12px; padding: 0; margin: 22px 0; list-style: none; }
.feature-list li, .check-list li { padding: 14px 16px; border: 1px solid var(--border); background: #fff; border-radius: 16px; color: #3A455B; }
.feature-list li strong, .check-list li strong { color: var(--text); }
.global-nodes-section { position: relative; background: #F7F9FF; overflow: hidden; }
.global-nodes-section::before {
    content: "";
    position: absolute;
    inset: 28px 0 auto;
    height: 360px;
    background:
        radial-gradient(circle at 18% 30%, rgba(41,128,254,.20), transparent 8%),
        radial-gradient(circle at 50% 45%, rgba(123,78,241,.18), transparent 9%),
        radial-gradient(circle at 78% 34%, rgba(184,77,218,.16), transparent 8%),
        linear-gradient(120deg, transparent 15%, rgba(41,128,254,.16) 15.4%, transparent 16%),
        linear-gradient(35deg, transparent 30%, rgba(123,78,241,.14) 30.4%, transparent 31%);
    opacity: .9;
}
.global-nodes-section .container { position: relative; z-index: 1; }
.node-map-panel {
    background: rgba(255,255,255,.86);
    border: 1px solid rgba(230,234,242,.9);
    border-radius: 32px;
    padding: 20px;
    box-shadow: var(--shadow);
}
.node-pills { display: flex; flex-wrap: wrap; gap: 10px; margin: 16px 0 0; }
.node-pills span { padding: 9px 12px; border-radius: 999px; background: #EDF4FF; color: #2B5FCA; font-weight: 800; font-size: 13px; }
.speed-card {
    border-radius: 28px;
    background: #fff;
    border: 1px solid var(--border);
    padding: 22px;
    box-shadow: var(--shadow);
}
.speed-line { height: 10px; border-radius: 999px; background: linear-gradient(90deg, #D8E7FF, #2980FE); margin: 14px 0 22px; }
.privacy-panel { display: grid; gap: 14px; }
.privacy-item { background: #fff; border: 1px solid var(--border); border-left: 5px solid var(--primary); border-radius: 18px; padding: 16px; }
.policy-grid, .feature-grid, .risk-grid, .faq-grid, .protocol-grid { display: grid; gap: 16px; }
.policy-card, .feature-card, .risk-card, .faq-item, .protocol-card { padding: 22px; }
.multi-device-section { background: linear-gradient(180deg, #fff 0%, #F7F9FF 100%); }
.device-grid { display: grid; gap: 16px; margin-top: 18px; }
.device-card { padding: 18px; border-radius: 20px; background: #fff; border: 1px solid var(--border); }
.tech-panel { background: #17213D; color: #fff; border-radius: 32px; padding: 24px; box-shadow: 0 26px 70px rgba(23,33,61,.22); }
.tech-panel p { color: rgba(255,255,255,.78); }
.protocol-stack { display: grid; gap: 12px; margin-top: 20px; }
.protocol-stack div { background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.15); border-radius: 18px; padding: 14px; }
.process-steps { display: grid; gap: 16px; counter-reset: step; }
.step-card { padding: 22px; position: relative; }
.step-num { display: inline-grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; background: var(--primary); color: #fff; font-weight: 900; margin-bottom: 12px; }
.risk-card { border-left: 5px solid var(--primary); }
.faq-item h3 { margin: 0 0 8px; font-size: 18px; }
.faq-item p { margin: 0; color: var(--muted); }
.cta-section { padding: 64px 0; background: var(--gradient); color: #fff; text-align: center; position: relative; overflow: hidden; }
.cta-section::before { content: ""; position: absolute; inset: 0; background: radial-gradient(circle at 50% 20%, rgba(255,255,255,.22), transparent 26%); }
.cta-section .container { position: relative; z-index: 1; }
.cta-section h2 { font-size: clamp(28px, 5vw, 46px); margin: 0 0 12px; letter-spacing: -.03em; }
.cta-section p { margin: 0 auto 24px; max-width: 720px; color: rgba(255,255,255,.86); }
.page-hero { padding: 58px 0 42px; background: linear-gradient(180deg, #F5F8FF 0%, #FFFFFF 100%); }
.page-hero h1 { margin: 14px 0 14px; font-size: clamp(34px, 6vw, 56px); line-height: 1.08; letter-spacing: -.04em; }
.page-hero p { color: var(--muted); max-width: 820px; margin: 0; font-size: 17px; }
.content-grid { display: grid; gap: 22px; align-items: start; }
.article-card { padding: 24px; }
.article-card h2 { margin-top: 0; font-size: 26px; }
.article-card p { color: #47536B; }
.side-panel { padding: 22px; position: sticky; top: 96px; }
.side-panel h3 { margin-top: 0; }
.info-list { display: grid; gap: 12px; padding: 0; margin: 0; list-style: none; }
.info-list li { padding: 13px 14px; background: var(--light); border-radius: 14px; color: #45516A; }
.single-cta { margin-top: 24px; padding-top: 22px; border-top: 1px solid var(--border); }
.download-steps { display: grid; gap: 16px; margin-top: 26px; }
.download-step { display: flex; gap: 14px; background: #fff; border: 1px solid var(--border); border-radius: 18px; padding: 18px; }
.download-step span { display: inline-grid; place-items: center; flex: 0 0 36px; width: 36px; height: 36px; border-radius: 50%; background: var(--primary); color: #fff; font-weight: 900; }
.site-footer { background: #17213D; color: #fff; padding: 56px 0 0; }
.footer-grid { display: grid; gap: 26px; }
.footer-grid p { color: rgba(255,255,255,.68); margin: 14px 0 0; }
.footer-grid h3 { margin: 0 0 12px; font-size: 16px; }
.footer-grid a { display: block; color: rgba(255,255,255,.72); margin: 8px 0; font-size: 14px; }
.footer-grid a:hover { color: #fff; }
.footer-bottom { margin-top: 36px; border-top: 1px solid rgba(255,255,255,.12); padding: 18px 24px; text-align: center; color: rgba(255,255,255,.62); font-size: 14px; }
@media (max-width: 860px) {
    .header-inner { min-height: 64px; }
    .nav-toggle-label { display: inline-flex; width: 42px; height: 42px; border-radius: 14px; background: #F1F5FF; flex-direction: column; justify-content: center; align-items: center; gap: 5px; cursor: pointer; }
    .nav-toggle-label span { width: 20px; height: 2px; background: #24304A; border-radius: 999px; }
    .site-nav { position: absolute; left: 14px; right: 14px; top: 70px; display: none; flex-direction: column; align-items: stretch; padding: 12px; border-radius: 22px; background: #fff; border: 1px solid var(--border); box-shadow: var(--shadow); }
    .site-nav a { padding: 12px 14px; }
    .nav-toggle:checked ~ .site-nav { display: flex; }
    .float-card { position: static; margin: 8px; display: inline-flex; }
    .hero-visual { min-height: auto; }
    .section { padding: 48px 0; }
    .side-panel { position: static; }
    .download-btn { width: auto; min-width: 150px; }
}
@media (min-width: 640px) {
    .node-overview-grid, .policy-grid, .feature-grid, .risk-grid, .faq-grid, .protocol-grid, .download-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .device-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}
@media (min-width: 900px) {
    .hero-inner { grid-template-columns: minmax(0, 1.02fr) minmax(320px, .98fr); align-items: center; min-height: 660px; }
    .split-section { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .node-overview-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
    .policy-grid.three, .feature-grid.three, .risk-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .process-steps { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .content-grid { grid-template-columns: minmax(0, 1fr) 330px; }
    .footer-grid { grid-template-columns: 1.4fr .8fr .8fr .8fr; }
}
@media (min-width: 1100px) {
    .process-steps.six { grid-template-columns: repeat(6, minmax(0, 1fr)); }
}