* {
    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: #233044;
    background: #f5f7fb;
    line-height: 1.7;
}

a {
    color: inherit;
    text-decoration: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.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, 232, 240, 0.9);
}

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

.header-inner {
    min-height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    color: #172033;
    letter-spacing: 0.02em;
}

.brand-logo {
    width: 38px;
    height: 38px;
    border-radius: 12px;
    object-fit: cover;
    box-shadow: 0 8px 22px rgba(41, 128, 254, 0.18);
}

.brand-text {
    font-size: 20px;
}

.nav-toggle {
    width: 44px;
    height: 44px;
    border: 1px solid #e5eaf2;
    border-radius: 14px;
    background: #fff;
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    cursor: pointer;
}

.nav-toggle span {
    width: 18px;
    height: 2px;
    border-radius: 99px;
    background: #172033;
}

.site-nav {
    position: absolute;
    top: 68px;
    left: 16px;
    right: 16px;
    display: none;
    grid-template-columns: 1fr;
    gap: 6px;
    padding: 14px;
    background: #fff;
    border: 1px solid #e5eaf2;
    border-radius: 20px;
    box-shadow: 0 24px 60px rgba(15, 23, 42, 0.12);
}

.site-nav.is-open {
    display: grid;
}

.site-nav a {
    padding: 10px 12px;
    border-radius: 12px;
    color: #4b5565;
    font-size: 15px;
}

.site-nav a:hover,
.site-nav a:focus {
    color: #2980FE;
    background: #eef5ff;
}

.nav-download {
    color: #2980FE !important;
    font-weight: 700;
}

.gradient-bg,
.vpn-network-hero,
.cta-section {
    background: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
}

.vpn-network-hero {
    position: relative;
    overflow: hidden;
    color: #fff;
    padding: 58px 0 76px;
}

.vpn-network-hero::before,
.vpn-network-hero::after {
    content: "";
    position: absolute;
    inset: auto;
    border-radius: 999px;
    pointer-events: none;
}

.vpn-network-hero::before {
    width: 360px;
    height: 360px;
    right: -120px;
    top: -90px;
    background: rgba(255,255,255,0.18);
    filter: blur(8px);
}

.vpn-network-hero::after {
    width: 520px;
    height: 180px;
    left: -110px;
    bottom: 20px;
    background: rgba(255,255,255,0.12);
    transform: rotate(-16deg);
}

.hero-grid {
    position: relative;
    z-index: 2;
    display: grid;
    gap: 34px;
    align-items: center;
}

.hero-copy h1 {
    margin: 0 0 16px;
    font-size: clamp(34px, 8vw, 64px);
    line-height: 1.08;
    letter-spacing: -0.04em;
}

.hero-copy p {
    margin: 0 0 22px;
    color: rgba(255,255,255,0.88);
    font-size: 17px;
}

.hero-tags,
.floating-tags,
.tag-row,
.badge-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.hero-tags span,
.floating-tags span,
.badge,
.security-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    border-radius: 999px;
    padding: 7px 12px;
    font-size: 13px;
    font-weight: 700;
}

.hero-tags span,
.floating-tags span {
    background: rgba(255,255,255,0.16);
    border: 1px solid rgba(255,255,255,0.24);
    color: #fff;
}

.hero-visual {
    position: relative;
    min-height: 340px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.node-orbit {
    position: absolute;
    width: min(92vw, 500px);
    aspect-ratio: 1;
    border-radius: 50%;
    border: 1px solid rgba(255,255,255,0.18);
    background:
        radial-gradient(circle at 20% 24%, rgba(255,255,255,0.75) 0 4px, transparent 5px),
        radial-gradient(circle at 76% 34%, rgba(255,255,255,0.62) 0 3px, transparent 4px),
        radial-gradient(circle at 42% 82%, rgba(255,255,255,0.55) 0 4px, transparent 5px),
        linear-gradient(135deg, rgba(255,255,255,0.08), rgba(255,255,255,0.02));
}

.hero-card {
    position: relative;
    z-index: 2;
    width: min(360px, 84vw);
    padding: 22px;
    background: rgba(255,255,255,0.14);
    border: 1px solid rgba(255,255,255,0.26);
    border-radius: 32px;
    box-shadow: 0 30px 80px rgba(15,23,42,0.2);
}

.hero-card img {
    width: 100%;
    border-radius: 26px;
    background: rgba(255,255,255,0.12);
}

.floating-card {
    position: absolute;
    z-index: 3;
    background: rgba(255,255,255,0.92);
    color: #172033;
    border: 1px solid rgba(255,255,255,0.8);
    border-radius: 18px;
    padding: 10px 13px;
    box-shadow: 0 18px 40px rgba(15,23,42,0.16);
    font-weight: 800;
    font-size: 13px;
}

.float-1 { left: 0; top: 28px; }
.float-2 { right: 0; top: 76px; }
.float-3 { left: 22px; bottom: 40px; }
.float-4 { right: 20px; bottom: 8px; }

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 26px;
    border-radius: 999px;
    background: #2980FE;
    color: #fff;
    font-weight: 800;
    box-shadow: 0 14px 32px rgba(41, 128, 254, 0.28);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}

.download-btn:hover,
.download-btn:focus {
    background: #1768E8;
    transform: translateY(-2px);
    box-shadow: 0 18px 38px rgba(23, 104, 232, 0.32);
}

.section {
    padding: 68px 0;
}

.section-soft {
    background: #eef4fb;
}

.section-title {
    margin: 0 0 12px;
    font-size: clamp(28px, 5vw, 42px);
    line-height: 1.18;
    color: #172033;
    letter-spacing: -0.03em;
}

.section-lead {
    margin: 0 0 28px;
    color: #5e6b7c;
    font-size: 16px;
}

.content-container {
    background: #fff;
    border: 1px solid #e6ecf4;
    border-radius: 28px;
    padding: 24px;
    box-shadow: 0 18px 50px rgba(15,23,42,0.06);
}

.node-overview {
    margin-top: -42px;
    position: relative;
    z-index: 5;
}

.node-grid,
.card-grid,
.policy-grid,
.risk-grid,
.faq-grid,
.quick-grid,
.steps-grid {
    display: grid;
    gap: 18px;
}

.node-card,
.feature-card,
.policy-card,
.risk-card,
.faq-item,
.step-card,
.help-card,
.note-card {
    background: #fff;
    border: 1px solid #e4ebf5;
    border-radius: 24px;
    padding: 22px;
    box-shadow: 0 16px 42px rgba(15,23,42,0.05);
}

.node-card .mini-label,
.badge,
.security-tag {
    background: #eef5ff;
    color: #2980FE;
}

.node-card h3,
.feature-card h3,
.policy-card h3,
.risk-card h3,
.step-card h3,
.help-card h3,
.note-card h3 {
    margin: 12px 0 8px;
    color: #172033;
    font-size: 20px;
}

.node-card p,
.feature-card p,
.policy-card p,
.risk-card p,
.step-card p,
.help-card p,
.note-card p,
.faq-item p {
    margin: 0;
    color: #5e6b7c;
}

.text-link {
    display: inline-flex;
    margin-top: 14px;
    color: #2980FE;
    font-weight: 800;
}

.split-section,
.vpn-connection-section,
.high-speed-section,
.privacy-protection-section,
.multi-device-section,
.encryption-protocol-section {
    display: grid;
    gap: 28px;
    align-items: center;
}

.visual-panel {
    background: #fff;
    border: 1px solid #e6ecf4;
    border-radius: 32px;
    padding: 18px;
    box-shadow: 0 22px 58px rgba(15,23,42,0.08);
}

.visual-panel img {
    border-radius: 24px;
    background: #f3f7ff;
}

.feature-list,
.check-list,
.number-list {
    list-style: none;
    padding: 0;
    margin: 18px 0 0;
    display: grid;
    gap: 10px;
}

.feature-list li,
.check-list li,
.number-list li {
    position: relative;
    padding-left: 28px;
    color: #4b5565;
}

.feature-list li::before,
.check-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 10px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: #2980FE;
    box-shadow: 0 0 0 5px #eaf3ff;
}

.global-nodes-section {
    position: relative;
    overflow: hidden;
    border-radius: 34px;
    padding: 30px;
    color: #fff;
    background:
        radial-gradient(circle at 16% 22%, rgba(255,255,255,.26) 0 3px, transparent 4px),
        radial-gradient(circle at 66% 30%, rgba(255,255,255,.24) 0 3px, transparent 4px),
        radial-gradient(circle at 82% 72%, rgba(255,255,255,.22) 0 3px, transparent 4px),
        linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
}

.global-nodes-section .section-title,
.global-nodes-section p,
.global-nodes-section li {
    color: #fff;
}

.global-nodes-section .node-info-card {
    background: rgba(255,255,255,0.14);
    border: 1px solid rgba(255,255,255,0.26);
    border-radius: 24px;
    padding: 18px;
}

.speed-lines {
    display: grid;
    gap: 12px;
    margin-top: 18px;
}

.speed-line {
    background: #fff;
    border: 1px solid #e6ecf4;
    border-radius: 18px;
    padding: 14px;
}

.speed-bar {
    height: 8px;
    border-radius: 999px;
    background: linear-gradient(90deg, #2980FE, #7B4EF1);
    margin-top: 10px;
}

.privacy-panel,
.tech-panel,
.safety-panel {
    background: #fff;
    border: 1px solid #e6ecf4;
    border-radius: 28px;
    padding: 24px;
    box-shadow: 0 20px 50px rgba(15,23,42,0.07);
}

.safety-panel {
    border-left: 5px solid #2980FE;
}

.protocol-stack {
    display: grid;
    gap: 12px;
}

.protocol-item {
    padding: 16px;
    border-radius: 18px;
    background: #f6f8fc;
    border: 1px solid #e6ecf4;
}

.process-steps .step-card {
    position: relative;
}

.step-number {
    width: 38px;
    height: 38px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 14px;
    background: #2980FE;
    color: #fff;
    font-weight: 900;
}

.risk-card {
    border-left: 4px solid #2980FE;
}

.risk-card strong {
    color: #172033;
}

.faq-item h3 {
    margin: 0 0 8px;
    font-size: 18px;
    color: #172033;
}

.cta-section {
    color: #fff;
    text-align: center;
    border-radius: 34px;
    padding: 46px 24px;
    overflow: hidden;
    position: relative;
}

.cta-section h2 {
    margin: 0 0 12px;
    font-size: clamp(28px, 6vw, 44px);
}

.cta-section p {
    width: min(720px, 100%);
    margin: 0 auto 24px;
    color: rgba(255,255,255,0.88);
}

.page-hero {
    padding: 54px 0;
    background: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    color: #fff;
}

.page-hero h1 {
    margin: 12px 0 14px;
    font-size: clamp(32px, 6vw, 52px);
    line-height: 1.14;
    letter-spacing: -0.03em;
}

.page-hero p {
    margin: 0;
    color: rgba(255,255,255,0.88);
    font-size: 17px;
}

.article-layout {
    display: grid;
    gap: 24px;
    align-items: start;
}

.article-main {
    display: grid;
    gap: 22px;
}

.article-card {
    background: #fff;
    border: 1px solid #e6ecf4;
    border-radius: 28px;
    padding: 24px;
    box-shadow: 0 18px 46px rgba(15,23,42,0.05);
}

.article-card h2 {
    margin: 0 0 12px;
    color: #172033;
    font-size: 26px;
}

.article-card p {
    color: #4b5565;
    margin: 0 0 14px;
}

.sidebar {
    display: grid;
    gap: 16px;
}

.sidebar .note-card {
    position: sticky;
    top: 92px;
}

.download-page-panel {
    display: grid;
    gap: 22px;
    text-align: center;
}

.download-steps {
    counter-reset: step;
    display: grid;
    gap: 14px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.download-steps li {
    counter-increment: step;
    background: #fff;
    border: 1px solid #e6ecf4;
    border-radius: 20px;
    padding: 18px;
    text-align: left;
}

.download-steps li::before {
    content: counter(step);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    margin-right: 10px;
    border-radius: 10px;
    background: #2980FE;
    color: #fff;
    font-weight: 900;
}

.site-footer {
    background: #172033;
    color: #c8d2df;
    padding: 52px 0 18px;
}

.footer-inner {
    display: grid;
    gap: 34px;
}

.footer-brand p {
    margin: 16px 0 0;
    max-width: 470px;
    color: #aab6c6;
}

.footer-brand-link .brand-text {
    color: #fff;
}

.footer-links {
    display: grid;
    gap: 22px;
}

.footer-links h3 {
    margin: 0 0 10px;
    color: #fff;
    font-size: 16px;
}

.footer-links a {
    display: block;
    padding: 4px 0;
    color: #aab6c6;
}

.footer-links a:hover {
    color: #fff;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    margin-top: 34px;
    padding-top: 18px;
    color: #8b99aa;
    font-size: 14px;
}

@media (min-width: 700px) {
    .node-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .card-grid,
    .policy-grid,
    .risk-grid,
    .faq-grid,
    .steps-grid,
    .quick-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .download-steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .footer-links { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (min-width: 920px) {
    .nav-toggle { display: none; }
    .site-nav {
        position: static;
        display: flex;
        align-items: center;
        gap: 2px;
        padding: 0;
        border: 0;
        box-shadow: none;
        background: transparent;
    }
    .site-nav a { padding: 8px 9px; font-size: 14px; }
    .hero-grid { grid-template-columns: 1.05fr .95fr; }
    .vpn-network-hero { padding: 76px 0 108px; }
    .node-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
    .split-section,
    .vpn-connection-section,
    .high-speed-section,
    .privacy-protection-section,
    .multi-device-section,
    .encryption-protocol-section { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .global-nodes-section { display: grid; grid-template-columns: 1fr .9fr; gap: 28px; align-items: center; padding: 42px; }
    .policy-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .risk-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .steps-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .article-layout { grid-template-columns: minmax(0, 1fr) 330px; }
    .footer-inner { grid-template-columns: .9fr 1.1fr; }
}

@media (min-width: 1120px) {
    .site-nav a { padding: 8px 12px; }
    .hero-copy p { font-size: 18px; }
}