:root {
    --primary: #2980FE;
    --primary-dark: #1768E8;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --text: #1f2937;
    --muted: #64748b;
    --light: #f6f8fc;
    --soft-blue: #eef5ff;
    --border: #e5eaf3;
    --white: #ffffff;
    --shadow: 0 18px 45px rgba(35, 59, 120, .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: 1.7;
    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.alt { background: var(--light); }
.section-title { max-width: 760px; margin: 0 0 28px; }
.section-title.center { margin-left: auto; margin-right: auto; text-align: center; }
.section-kicker, .page-badge, .mini-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--primary);
    background: rgba(41, 128, 254, .10);
    border: 1px solid rgba(41, 128, 254, .18);
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
}
h1, h2, h3 { line-height: 1.25; color: #15213a; margin-top: 0; }
h1 { font-size: clamp(32px, 7vw, 58px); letter-spacing: -1.2px; }
h2 { font-size: clamp(26px, 4vw, 40px); }
h3 { font-size: 20px; }
p { margin: 0 0 16px; }
.lead { color: #eaf1ff; font-size: 18px; max-width: 620px; }
.muted { color: var(--muted); }

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255,255,255,.92);
    backdrop-filter: blur(14px);
    border-bottom: 1px solid rgba(226,232,240,.8);
}
.nav-wrap {
    width: min(1180px, calc(100% - 28px));
    margin: 0 auto;
    min-height: 70px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; flex: 0 0 auto; }
.brand-logo { width: 40px; height: 40px; border-radius: 12px; object-fit: cover; box-shadow: 0 8px 20px rgba(41,128,254,.18); }
.brand-name { font-weight: 900; color: #122042; font-size: 21px; letter-spacing: .5px; }
.site-nav {
    position: absolute;
    left: 14px;
    right: 14px;
    top: 76px;
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: 14px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 20px;
    box-shadow: var(--shadow);
}
.site-nav.is-open { display: flex; }
.site-nav a { color: #475569; font-size: 14px; font-weight: 700; padding: 10px 12px; border-radius: 12px; }
.site-nav a:hover, .site-nav a.active { color: var(--primary); background: var(--soft-blue); }
.nav-toggle {
    display: inline-flex;
    width: 42px;
    height: 42px;
    border: 1px solid var(--border);
    background: #fff;
    border-radius: 12px;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}
.nav-toggle span { width: 18px; height: 2px; background: #1f2937; border-radius: 8px; }

.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 14px 28px 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 18px 34px rgba(23, 104, 232, .28); }
.link-arrow { color: var(--primary); font-weight: 800; }
.link-arrow:hover { color: var(--primary-dark); }

.vpn-network-hero {
    position: relative;
    overflow: hidden;
    color: #fff;
    background: var(--gradient);
    padding: 66px 0 48px;
}
.vpn-network-hero::before, .vpn-network-hero::after {
    content: "";
    position: absolute;
    border-radius: 999px;
    pointer-events: none;
}
.vpn-network-hero::before {
    width: 520px;
    height: 520px;
    top: -230px;
    right: -160px;
    background: radial-gradient(circle, rgba(255,255,255,.28), rgba(255,255,255,0) 62%);
}
.vpn-network-hero::after {
    inset: 0;
    background:
        radial-gradient(circle at 18% 35%, rgba(255,255,255,.24) 0 3px, transparent 4px),
        radial-gradient(circle at 72% 30%, rgba(255,255,255,.22) 0 3px, transparent 4px),
        radial-gradient(circle at 56% 74%, rgba(255,255,255,.20) 0 3px, transparent 4px),
        linear-gradient(120deg, transparent 18%, rgba(255,255,255,.20) 18.2%, transparent 18.6%, transparent 48%, rgba(255,255,255,.12) 48.2%, transparent 48.8%);
    opacity: .55;
}
.hero-grid { position: relative; z-index: 1; display: grid; gap: 32px; align-items: center; }
.hero-copy h1 { color: #fff; margin-bottom: 18px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; margin: 22px 0 28px; }
.hero-tags span, .floating-label {
    display: inline-flex;
    align-items: center;
    color: #fff;
    background: rgba(255,255,255,.16);
    border: 1px solid rgba(255,255,255,.28);
    padding: 7px 12px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
    backdrop-filter: blur(10px);
}
.hero-visual { position: relative; min-height: 320px; }
.hero-device {
    position: relative;
    z-index: 2;
    width: min(420px, 88%);
    margin: 0 auto;
    border-radius: 32px;
    box-shadow: 0 28px 70px rgba(0,0,0,.25);
}
.node-orbit {
    position: absolute;
    inset: 22px;
    border: 1px solid rgba(255,255,255,.22);
    border-radius: 40px;
    transform: rotate(-5deg);
}
.floating-label { position: absolute; z-index: 3; box-shadow: 0 16px 34px rgba(0,0,0,.16); }
.label-one { top: 18px; left: 0; }
.label-two { top: 72px; right: 0; }
.label-three { bottom: 58px; left: 6px; }
.label-four { bottom: 18px; right: 10px; }

.node-overview { margin-top: -34px; position: relative; z-index: 5; }
.node-grid { display: grid; gap: 16px; }
.node-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 22px;
    box-shadow: var(--shadow);
}
.node-card .tag { color: var(--primary); font-weight: 900; font-size: 13px; }
.node-card h3 { margin: 8px 0; }
.node-card p { color: var(--muted); font-size: 15px; }

.split-section, .feature-split {
    display: grid;
    gap: 28px;
    align-items: center;
}
.visual-panel {
    border-radius: 30px;
    padding: 18px;
    background: linear-gradient(145deg, #ffffff, #edf4ff);
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
}
.visual-panel img { border-radius: 24px; }
.feature-list { display: grid; gap: 12px; margin: 22px 0; }
.feature-list li, .check-list li {
    list-style: none;
    position: relative;
    padding-left: 28px;
    color: #475569;
}
.feature-list li::before, .check-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: .62em;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--primary);
    box-shadow: 0 0 0 5px rgba(41,128,254,.12);
}
.global-nodes-section {
    background: linear-gradient(180deg, #f7fbff 0%, #fff 100%);
    position: relative;
    overflow: hidden;
}
.global-map-card {
    position: relative;
    border-radius: 32px;
    padding: 22px;
    min-height: 300px;
    background:
        radial-gradient(circle at 30% 26%, rgba(41,128,254,.18), transparent 28%),
        radial-gradient(circle at 75% 60%, rgba(123,78,241,.16), transparent 28%),
        #fff;
    border: 1px solid var(--border);
    box-shadow: var(--shadow);
}
.global-map-card::before {
    content: "";
    position: absolute;
    inset: 28px;
    border-radius: 26px;
    background:
        linear-gradient(25deg, transparent 34%, rgba(41,128,254,.18) 34.4%, transparent 35.2%),
        linear-gradient(145deg, transparent 30%, rgba(184,77,218,.16) 30.4%, transparent 31.2%);
}
.global-map-card img { position: relative; z-index: 1; width: min(420px, 88%); margin: 18px auto 0; border-radius: 26px; }
.node-chip-list { position: relative; z-index: 2; display: flex; flex-wrap: wrap; gap: 10px; }
.node-chip-list span { background: #fff; border: 1px solid var(--border); color: #40506b; border-radius: 999px; padding: 8px 12px; font-size: 13px; font-weight: 700; }
.speed-card {
    border-radius: 28px;
    border: 1px solid var(--border);
    background: #fff;
    padding: 24px;
    box-shadow: var(--shadow);
}
.speed-line { height: 10px; border-radius: 999px; background: #e8eef8; margin: 16px 0; overflow: hidden; }
.speed-line span { display: block; height: 100%; width: 76%; background: var(--primary); border-radius: inherit; }
.privacy-panel, .tech-panel, .safety-panel {
    border: 1px solid var(--border);
    border-radius: 28px;
    background: #fff;
    padding: 24px;
    box-shadow: var(--shadow);
}
.privacy-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.privacy-tags span { background: var(--soft-blue); color: var(--primary); border-radius: 999px; padding: 7px 11px; font-weight: 800; font-size: 13px; }
.policy-grid, .device-grid, .protocol-grid, .risk-grid, .faq-grid, .card-grid { display: grid; gap: 16px; }
.info-card, .policy-card, .device-card, .protocol-card, .risk-card, .faq-item, .step-card {
    border: 1px solid var(--border);
    border-radius: 22px;
    background: #fff;
    padding: 22px;
    box-shadow: 0 12px 34px rgba(35, 59, 120, .07);
}
.risk-card { border-left: 4px solid var(--primary); }
.device-card img { border-radius: 18px; margin-bottom: 14px; background: var(--light); }
.protocol-card { background: linear-gradient(180deg, #fff 0%, #f8fbff 100%); }
.process-steps { display: grid; gap: 16px; counter-reset: step; }
.step-card { position: relative; padding-top: 54px; }
.step-card::before {
    counter-increment: step;
    content: counter(step, decimal-leading-zero);
    position: absolute;
    top: 18px;
    left: 22px;
    color: var(--primary);
    font-weight: 900;
    letter-spacing: .6px;
}
.cta-section {
    padding: 70px 0;
    color: #fff;
    background: var(--gradient);
    text-align: center;
    position: relative;
    overflow: hidden;
}
.cta-section::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 20% 30%, rgba(255,255,255,.18), transparent 30%), radial-gradient(circle at 80% 70%, rgba(255,255,255,.16), transparent 32%);
}
.cta-section .container { position: relative; z-index: 1; }
.cta-section h2 { color: #fff; }
.cta-section p { color: #eaf1ff; max-width: 720px; margin-left: auto; margin-right: auto; }

.page-hero {
    padding: 56px 0 42px;
    background: linear-gradient(180deg, #f4f8ff 0%, #fff 100%);
    border-bottom: 1px solid var(--border);
}
.compact-hero h1 { margin: 14px 0 12px; max-width: 880px; }
.compact-hero p { color: var(--muted); max-width: 760px; font-size: 17px; }
.article-section { padding: 52px 0 68px; background: #fff; }
.article-layout { display: grid; gap: 22px; }
.article-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 28px;
    padding: 24px;
    box-shadow: var(--shadow);
}
.article-card h2 { font-size: 26px; margin-top: 26px; }
.article-card h2:first-child { margin-top: 0; }
.article-card p { color: #46556e; }
.article-card .download-btn { margin-top: 12px; }
.side-panel { display: grid; gap: 16px; align-content: start; }
.side-box {
    background: #f8fbff;
    border: 1px solid var(--border);
    border-radius: 22px;
    padding: 20px;
}
.side-box a { display: block; color: var(--primary); font-weight: 800; margin-top: 8px; }
.notice-box {
    background: var(--soft-blue);
    border: 1px solid rgba(41,128,254,.16);
    border-radius: 20px;
    padding: 18px;
    margin: 18px 0;
    color: #365176;
}
.number-list { padding-left: 20px; color: #46556e; }
.number-list li { margin-bottom: 10px; }
.faq-list { display: grid; gap: 14px; }
.faq-list .faq-item h2 { font-size: 20px; margin-bottom: 8px; }
.download-panel {
    max-width: 760px;
    margin: 0 auto;
    text-align: center;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 30px;
    padding: 30px;
    box-shadow: var(--shadow);
}
.download-steps { text-align: left; margin-top: 28px; }
.site-footer { background: #111b31; color: #d7deea; padding-top: 48px; }
.footer-grid { display: grid; gap: 28px; }
.footer-brand { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; color: #fff; }
.footer-brand img { width: 38px; height: 38px; border-radius: 12px; }
.site-footer h3 { color: #fff; font-size: 16px; }
.site-footer a { display: block; color: #d7deea; margin: 8px 0; font-size: 14px; }
.site-footer a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.10); margin-top: 34px; padding: 18px; text-align: center; color: #aab5c7; font-size: 14px; }

@media (min-width: 680px) {
    .node-grid, .policy-grid, .device-grid, .protocol-grid, .risk-grid, .faq-grid, .card-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .process-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .article-card { padding: 34px; }
}

@media (min-width: 980px) {
    .nav-toggle { display: none; }
    .site-nav { position: static; display: flex; flex-direction: row; align-items: center; gap: 2px; padding: 0; border: 0; box-shadow: none; background: transparent; }
    .site-nav a { padding: 9px 11px; }
    .vpn-network-hero { padding: 92px 0 86px; }
    .hero-grid, .split-section, .feature-split { grid-template-columns: 1.05fr .95fr; }
    .node-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
    .policy-grid, .protocol-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .device-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .risk-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
    .faq-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .process-steps { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .article-layout { grid-template-columns: minmax(0, 1fr) 310px; align-items: start; }
    .footer-grid { grid-template-columns: 1.4fr .8fr .8fr .8fr; }
    .section { padding: 86px 0; }
}

@media (max-width: 520px) {
    .container { width: min(100% - 24px, 1120px); }
    .download-btn { width: 100%; min-height: 52px; }
    .hero-visual { min-height: 280px; }
    .floating-label { font-size: 12px; padding: 6px 9px; }
    .article-card, .download-panel { padding: 20px; border-radius: 22px; }
}