:root {
    --primary: #2980FE;
    --primary-hover: #1768E8;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --text: #1f2937;
    --muted: #64748b;
    --soft: #f5f7fb;
    --line: #e5eaf3;
    --card: #ffffff;
    --radius-lg: 28px;
    --radius-md: 20px;
    --shadow: 0 18px 50px rgba(40, 65, 120, 0.12);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "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%;
    display: block;
}

.container {
    width: min(1120px, calc(100% - 32px));
    margin: 0 auto;
}

.container.narrow {
    width: min(860px, calc(100% - 32px));
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.94);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--line);
}

.header-inner {
    width: min(1180px, calc(100% - 28px));
    margin: 0 auto;
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    color: #172554;
}

.logo {
    width: 38px;
    height: 38px;
    border-radius: 12px;
    object-fit: cover;
}

.brand-text {
    font-size: 18px;
    letter-spacing: 0.02em;
}

.site-nav {
    display: none;
    position: absolute;
    left: 14px;
    right: 14px;
    top: 72px;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 18px;
    box-shadow: var(--shadow);
    padding: 12px;
}

.site-nav a {
    display: block;
    padding: 11px 12px;
    color: #334155;
    border-radius: 12px;
    font-size: 14px;
}

.site-nav a.active,
.site-nav a:hover {
    color: var(--primary);
    background: #eef5ff;
}

.nav-toggle {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.nav-toggle-label {
    display: inline-flex;
    width: 44px;
    height: 44px;
    border: 1px solid var(--line);
    border-radius: 14px;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.nav-toggle-label span {
    width: 18px;
    height: 2px;
    background: #1e293b;
    border-radius: 10px;
}

.nav-toggle:checked ~ .site-nav {
    display: block;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 26px;
    border-radius: 999px;
    background: #2980FE;
    color: #fff;
    font-weight: 800;
    box-shadow: 0 14px 28px rgba(41, 128, 254, 0.28);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}

.download-btn:hover {
    background: #1768E8;
    transform: translateY(-2px);
    box-shadow: 0 18px 34px rgba(23, 104, 232, 0.30);
}

.vpn-network-hero {
    position: relative;
    isolation: isolate;
    min-height: 680px;
    padding: 72px 0 64px;
    color: #fff;
    background: var(--gradient);
    overflow: hidden;
}

.network-lines {
    position: absolute;
    inset: 0;
    z-index: -1;
    background:
        radial-gradient(circle at 15% 22%, rgba(255,255,255,.28), transparent 18%),
        radial-gradient(circle at 70% 20%, rgba(255,255,255,.20), transparent 15%),
        radial-gradient(circle at 80% 76%, rgba(255,255,255,.18), transparent 18%),
        linear-gradient(135deg, transparent 0 46%, rgba(255,255,255,.18) 47%, transparent 48% 100%);
}

.network-lines::after {
    content: "";
    position: absolute;
    inset: 8% 4%;
    border: 1px solid rgba(255,255,255,.18);
    border-radius: 40px;
    background-image:
        linear-gradient(90deg, rgba(255,255,255,.13) 1px, transparent 1px),
        linear-gradient(180deg, rgba(255,255,255,.11) 1px, transparent 1px);
    background-size: 72px 72px;
    opacity: .35;
}

.hero-grid,
.split-grid,
.nodes-map-grid,
.privacy-grid,
.protocol-grid,
.two-column,
.article-layout {
    display: grid;
    gap: 28px;
}

.hero-copy {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 18px;
}

.eyebrow,
.section-kicker,
.badge {
    display: inline-flex;
    align-items: center;
    width: max-content;
    padding: 7px 12px;
    border-radius: 999px;
    background: #eef5ff;
    color: var(--primary);
    font-size: 13px;
    font-weight: 800;
}

.eyebrow {
    background: rgba(255,255,255,.18);
    color: #fff;
    border: 1px solid rgba(255,255,255,.24);
}

.section-kicker.light {
    background: rgba(255,255,255,.18);
    color: #fff;
}

h1, h2, h3 {
    margin: 0;
    line-height: 1.25;
    color: #111827;
}

.vpn-network-hero h1 {
    color: #fff;
    font-size: clamp(34px, 8vw, 64px);
    letter-spacing: -0.04em;
}

.vpn-network-hero p {
    margin: 0;
    max-width: 620px;
    color: rgba(255,255,255,.88);
    font-size: 17px;
}

.hero-tags,
.pill-row,
.mini-metrics,
.speed-lines,
.device-cards,
.protocol-stack {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.hero-tags span,
.mini-metrics span,
.speed-lines span,
.device-cards span,
.protocol-stack span,
.pill-row span {
    display: inline-flex;
    border-radius: 999px;
    padding: 8px 12px;
    font-size: 13px;
    font-weight: 700;
}

.hero-tags span {
    background: rgba(255,255,255,.16);
    border: 1px solid rgba(255,255,255,.24);
}

.visual-card {
    position: relative;
    margin: 10px auto 0;
    max-width: 470px;
    padding: 20px;
    border-radius: 34px;
    background: rgba(255,255,255,.16);
    border: 1px solid rgba(255,255,255,.28);
    box-shadow: 0 34px 90px rgba(20, 20, 80, .28);
}

.visual-card img {
    border-radius: 26px;
}

.float-tag {
    position: absolute;
    padding: 9px 13px;
    border-radius: 999px;
    background: #fff;
    color: #1e293b;
    font-size: 13px;
    font-weight: 800;
    box-shadow: 0 12px 30px rgba(15, 23, 42, .15);
}

.tag-a { left: 0; top: 18%; }
.tag-b { right: -2%; top: 30%; }
.tag-c { left: 8%; bottom: 12%; }
.tag-d { right: 8%; bottom: 4%; }

section {
    padding: 72px 0;
}

.section-heading {
    margin-bottom: 30px;
}

.section-heading.centered {
    text-align: center;
    margin-left: auto;
    margin-right: auto;
    max-width: 760px;
}

.section-heading h2,
.content-panel h2,
.page-hero h1 {
    font-size: clamp(28px, 5vw, 42px);
    letter-spacing: -0.03em;
}

.section-heading p,
.content-panel p,
.page-hero p,
.article-card p,
.faq-item p,
.side-panel p {
    color: var(--muted);
    margin: 12px 0 0;
}

.node-overview {
    display: grid;
    gap: 16px;
}

.node-card,
.article-card,
.side-panel,
.faq-item,
.policy-grid article,
.process-steps article,
.risk-grid article,
.notice-box,
.tip-grid article,
.info-strip {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: var(--radius-md);
    box-shadow: 0 12px 32px rgba(15, 23, 42, .05);
}

.node-card {
    padding: 22px;
}

.node-card span {
    display: inline-flex;
    background: #eef5ff;
    color: var(--primary);
    font-weight: 800;
    font-size: 12px;
    padding: 5px 10px;
    border-radius: 999px;
}

.node-card h3 {
    margin-top: 14px;
    font-size: 21px;
}

.node-card p {
    margin: 10px 0 18px;
    color: var(--muted);
}

.node-card a,
.text-link,
.related-links a,
.process-steps a,
.risk-grid a {
    color: var(--primary);
    font-weight: 800;
}

.feature-split,
.privacy-protection-section,
.node-overview-section,
.faq-summary-section {
    background: #fff;
}

.soft-bg,
.high-speed-section,
.risk-section {
    background: #f6f8fc;
}

.content-panel {
    align-self: center;
}

.image-panel,
.map-panel,
.privacy-panel,
.protocol-panel {
    position: relative;
    border-radius: var(--radius-lg);
    background: #fff;
    border: 1px solid var(--line);
    padding: 18px;
    box-shadow: var(--shadow);
}

.image-panel img,
.map-panel img,
.privacy-panel img,
.protocol-panel img {
    border-radius: 22px;
}

.check-list {
    margin: 18px 0;
    padding: 0;
    list-style: none;
}

.check-list li {
    position: relative;
    padding: 9px 0 9px 30px;
    color: #334155;
}

.check-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 14px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary);
    box-shadow: inset 0 0 0 5px #dcecff;
}

.global-nodes-section {
    position: relative;
    background:
        radial-gradient(circle at 70% 30%, rgba(41,128,254,.10), transparent 28%),
        radial-gradient(circle at 18% 70%, rgba(123,78,241,.10), transparent 26%),
        #fff;
}

.map-panel::before {
    content: "";
    position: absolute;
    inset: 36px;
    border: 1px dashed rgba(41,128,254,.35);
    border-radius: 28px;
    pointer-events: none;
}

.map-card,
.safe-card {
    margin-top: 14px;
    padding: 16px;
    border-radius: 18px;
    background: #f8fbff;
    border: 1px solid #dcecff;
    color: #334155;
}

.mini-metrics span,
.speed-lines span,
.device-cards span,
.protocol-stack span,
.pill-row span {
    background: #eef5ff;
    color: #1d4ed8;
}

.policy-grid,
.process-steps,
.risk-grid,
.tip-grid {
    display: grid;
    gap: 16px;
}

.policy-grid article,
.process-steps article,
.risk-grid article,
.tip-grid article {
    padding: 22px;
}

.policy-grid p,
.process-steps p,
.risk-grid p {
    color: var(--muted);
    margin: 8px 0 0;
}

.center-link {
    text-align: center;
    margin-top: 26px;
}

.protocol-panel {
    display: grid;
    gap: 16px;
}

.protocol-stack {
    justify-content: center;
}

.process-steps article b {
    display: inline-flex;
    width: 42px;
    height: 42px;
    border-radius: 15px;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    color: #fff;
    margin-bottom: 14px;
}

.risk-grid article {
    border-left: 4px solid var(--primary);
}

.risk-grid strong {
    display: block;
    margin: 10px 0;
    color: #334155;
    font-size: 14px;
}

.faq-list {
    display: grid;
    gap: 14px;
}

.faq-item {
    padding: 22px;
}

.faq-list.large .faq-item h2 {
    font-size: 22px;
}

.cta-section {
    background: var(--gradient);
    color: #fff;
    text-align: center;
}

.cta-section h2 {
    color: #fff;
    font-size: clamp(30px, 6vw, 46px);
}

.cta-section p {
    color: rgba(255,255,255,.86);
    max-width: 680px;
    margin: 14px auto 24px;
}

.page-hero {
    background:
        radial-gradient(circle at 15% 20%, rgba(41,128,254,.12), transparent 26%),
        radial-gradient(circle at 85% 10%, rgba(184,77,218,.12), transparent 24%),
        #f8fbff;
    text-align: center;
}

.page-hero.compact {
    padding: 64px 0 58px;
}

.content-section {
    background: #fff;
}

.article-card {
    padding: 26px;
}

.article-card h2 {
    margin-top: 26px;
    font-size: 26px;
}

.article-card h2:first-child {
    margin-top: 0;
}

.article-card .download-btn {
    margin-top: 22px;
}

.side-panel {
    padding: 24px;
    height: max-content;
}

.side-panel h2,
.side-panel h3 {
    font-size: 20px;
    margin-bottom: 12px;
}

.side-panel ul,
.number-list {
    margin: 0;
    padding-left: 20px;
    color: #475569;
}

.side-panel li,
.number-list li {
    margin: 10px 0;
}

.related-links {
    margin-top: 22px;
    padding-top: 18px;
    border-top: 1px solid var(--line);
    display: grid;
    gap: 10px;
}

.notice-box,
.info-strip {
    margin-top: 22px;
    padding: 18px;
    background: #f8fbff;
    border-color: #dcecff;
}

.tip-grid {
    margin-top: 22px;
}

.tip-grid article {
    display: grid;
    gap: 4px;
    box-shadow: none;
}

.tip-grid span {
    color: var(--muted);
}

.number-list strong {
    color: #111827;
}

.site-footer {
    background: #111827;
    color: #cbd5e1;
    padding-top: 54px;
}

.footer-grid {
    display: grid;
    gap: 28px;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    color: #fff;
    margin-bottom: 12px;
}

.footer-brand img {
    width: 36px;
    height: 36px;
    border-radius: 12px;
    object-fit: cover;
}

.site-footer h3 {
    color: #fff;
    font-size: 16px;
    margin-bottom: 12px;
}

.site-footer a {
    display: block;
    color: #cbd5e1;
    margin: 8px 0;
}

.site-footer p {
    margin: 0;
    color: #94a3b8;
}

.footer-bottom {
    margin-top: 34px;
    padding: 18px;
    border-top: 1px solid rgba(255,255,255,.10);
    text-align: center;
    color: #94a3b8;
    font-size: 14px;
}

@media (min-width: 640px) {
    .node-overview,
    .policy-grid,
    .risk-grid,
    .tip-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    .process-steps {
        grid-template-columns: repeat(2, 1fr);
    }
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 900px) {
    .site-nav {
        position: static;
        display: flex;
        align-items: center;
        gap: 2px;
        padding: 0;
        border: 0;
        box-shadow: none;
        background: transparent;
    }

    .site-nav a {
        display: inline-flex;
        padding: 9px 11px;
    }

    .nav-toggle-label {
        display: none;
    }

    .hero-grid {
        grid-template-columns: 1.04fr .96fr;
        align-items: center;
    }

    .split-grid,
    .nodes-map-grid,
    .privacy-grid,
    .protocol-grid,
    .two-column,
    .article-layout {
        grid-template-columns: 1fr 1fr;
        align-items: start;
    }

    .article-layout {
        grid-template-columns: minmax(0, 1fr) 320px;
    }

    .article-layout.alt {
        grid-template-columns: 330px minmax(0, 1fr);
    }

    .article-layout.alt .article-card {
        order: 2;
    }

    .article-layout.alt .side-panel {
        order: 1;
    }

    .reverse .content-panel {
        order: 2;
    }

    .reverse .image-panel {
        order: 1;
    }

    .node-overview {
        grid-template-columns: repeat(4, 1fr);
    }

    .policy-grid,
    .risk-grid,
    .footer-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .risk-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .process-steps {
        grid-template-columns: repeat(3, 1fr);
    }

    .vpn-network-hero {
        padding: 96px 0 86px;
    }

    .article-card {
        padding: 34px;
    }
}

@media (max-width: 520px) {
    .container {
        width: min(100% - 24px, 1120px);
    }

    .header-inner {
        width: calc(100% - 22px);
    }

    section {
        padding: 52px 0;
    }

    .vpn-network-hero {
        min-height: auto;
        padding: 56px 0;
    }

    .visual-card {
        padding: 12px;
        border-radius: 24px;
    }

    .float-tag {
        position: static;
        display: inline-flex;
        margin: 8px 5px 0 0;
    }

    .download-btn {
        width: 100%;
        min-height: 52px;
    }

    .hero-copy .download-btn,
    .cta-section .download-btn {
        width: auto;
        min-width: 168px;
    }

    .article-card,
    .side-panel,
    .faq-item,
    .node-card {
        padding: 20px;
    }
}