* {
    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: #1f2937;
    background: #f6f8fc;
    line-height: 1.75;
}

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 #e5e7eb;
}

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

.logo,
.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    color: #111827;
    letter-spacing: 0.02em;
}

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

.nav-check {
    display: none;
}

.nav-toggle {
    width: 42px;
    height: 42px;
    display: grid;
    place-items: center;
    gap: 4px;
    padding: 10px;
    border-radius: 14px;
    border: 1px solid #e5e7eb;
    cursor: pointer;
    background: #ffffff;
}

.nav-toggle span {
    display: block;
    width: 18px;
    height: 2px;
    background: #1f2937;
    border-radius: 999px;
}

.site-nav {
    position: absolute;
    top: 68px;
    left: 16px;
    right: 16px;
    display: none;
    flex-direction: column;
    gap: 8px;
    padding: 14px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 20px;
    box-shadow: 0 18px 45px rgba(31, 41, 55, 0.12);
}

.nav-check:checked ~ .site-nav {
    display: flex;
}

.site-nav a {
    padding: 10px 12px;
    color: #4b5563;
    border-radius: 12px;
    font-size: 15px;
}

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

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 12px 26px;
    border-radius: 999px;
    background: #2980FE;
    color: #ffffff;
    font-weight: 800;
    line-height: 1;
    box-shadow: 0 14px 32px rgba(41, 128, 254, 0.28);
    transition: transform 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
}

.download-btn:hover {
    background: #1768E8;
    transform: translateY(-2px);
    box-shadow: 0 18px 36px rgba(23, 104, 232, 0.32);
}

.section {
    padding: 64px 0;
}

.section-light {
    background: #ffffff;
}

.section-soft {
    background: #edf3fb;
}

.section-head {
    max-width: 760px;
    margin-bottom: 28px;
}

.center-head {
    text-align: center;
    margin-left: auto;
    margin-right: auto;
}

.eyebrow,
.badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    min-height: 28px;
    padding: 4px 10px;
    border-radius: 999px;
    color: #2980FE;
    background: #eef5ff;
    border: 1px solid #d9e9ff;
    font-size: 13px;
    font-weight: 800;
}

h1,
h2,
h3 {
    margin: 0 0 14px;
    color: #111827;
    line-height: 1.18;
}

h1 {
    font-size: clamp(34px, 9vw, 64px);
    letter-spacing: -0.05em;
}

h2 {
    font-size: clamp(28px, 5vw, 42px);
    letter-spacing: -0.03em;
}

h3 {
    font-size: 20px;
}

p {
    margin: 0 0 14px;
    color: #4b5563;
}

.vpn-network-hero {
    position: relative;
    overflow: hidden;
    padding: 76px 0 60px;
    color: #ffffff;
    background: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
}

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

.vpn-network-hero::before {
    width: 520px;
    height: 520px;
    right: -160px;
    top: -190px;
    background: rgba(255, 255, 255, 0.18);
}

.vpn-network-hero::after {
    width: 760px;
    height: 1px;
    left: 8%;
    top: 43%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,.48), transparent);
    box-shadow: 0 80px 0 rgba(255,255,255,.14), 0 -80px 0 rgba(255,255,255,.12);
}

.hero-grid {
    position: relative;
    z-index: 2;
    display: grid;
    gap: 38px;
    align-items: center;
}

.hero-content h1,
.hero-content p {
    color: #ffffff;
}

.hero-content p {
    max-width: 720px;
    color: rgba(255, 255, 255, 0.88);
    font-size: 18px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 14px;
    margin: 24px 0;
}

.hero-note {
    color: rgba(255,255,255,.88);
    font-size: 14px;
}

.hero-tags,
.status-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.hero-tags span,
.status-tags span {
    display: inline-flex;
    align-items: center;
    min-height: 32px;
    padding: 6px 12px;
    border-radius: 999px;
    color: #ffffff;
    background: rgba(255,255,255,.14);
    border: 1px solid rgba(255,255,255,.24);
    font-size: 13px;
    backdrop-filter: blur(10px);
}

.hero-visual {
    position: relative;
    min-height: 360px;
    display: grid;
    place-items: center;
}

.hero-device {
    position: relative;
    width: min(430px, 88%);
    padding: 22px;
    border-radius: 34px;
    background: rgba(255,255,255,.18);
    box-shadow: 0 30px 80px rgba(17, 24, 39, 0.28);
    border: 1px solid rgba(255,255,255,.22);
}

.hero-device img {
    border-radius: 26px;
    margin: auto;
}

.float-card {
    position: absolute;
    display: none;
    padding: 10px 14px;
    border-radius: 16px;
    background: rgba(255,255,255,.92);
    color: #111827;
    box-shadow: 0 16px 36px rgba(17,24,39,.16);
    font-size: 13px;
    font-weight: 800;
}

.float-card.one { top: 12%; left: 2%; }
.float-card.two { top: 24%; right: 2%; }
.float-card.three { bottom: 24%; left: 0; }
.float-card.four { bottom: 12%; right: 4%; }

.node-overview {
    margin-top: -34px;
    position: relative;
    z-index: 3;
}

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

.node-card,
.info-card,
.policy-card,
.risk-card,
.faq-item,
.help-card,
.feature-card {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 24px;
    padding: 22px;
    box-shadow: 0 16px 40px rgba(31, 41, 55, 0.06);
}

.node-card .mini-label,
.info-card .mini-label {
    display: inline-flex;
    margin-bottom: 12px;
    padding: 3px 9px;
    border-radius: 999px;
    background: #eef5ff;
    color: #2980FE;
    font-size: 12px;
    font-weight: 800;
}

.card-link,
.text-link {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    margin-top: 6px;
    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: 30px;
    align-items: center;
}

.visual-panel {
    position: relative;
    padding: 20px;
    border-radius: 32px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    box-shadow: 0 20px 52px rgba(31, 41, 55, 0.08);
}

.visual-panel img {
    width: 100%;
    border-radius: 24px;
}

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

.feature-list li,
.check-list li,
.clean-list li {
    position: relative;
    padding-left: 26px;
    color: #4b5563;
}

.feature-list li::before,
.check-list li::before,
.clean-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 12px;
    width: 10px;
    height: 10px;
    border-radius: 999px;
    background: #2980FE;
    box-shadow: 0 0 0 5px #eef5ff;
}

.global-nodes-section {
    position: relative;
    overflow: hidden;
    border-radius: 36px;
    padding: 34px;
    background: radial-gradient(circle at 30% 20%, rgba(41,128,254,.18), transparent 28%), linear-gradient(135deg, #ffffff 0%, #f3f7ff 100%);
    border: 1px solid #e0e8f5;
}

.global-nodes-section::before {
    content: "";
    position: absolute;
    inset: 34px;
    border-radius: 30px;
    background-image: linear-gradient(90deg, rgba(41,128,254,.1) 1px, transparent 1px), linear-gradient(rgba(41,128,254,.1) 1px, transparent 1px);
    background-size: 48px 48px;
    opacity: .56;
}

.global-content {
    position: relative;
    display: grid;
    gap: 28px;
    align-items: center;
}

.node-status {
    display: grid;
    gap: 12px;
    margin-top: 18px;
}

.node-status span {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    padding: 12px 14px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 16px;
    color: #4b5563;
}

.speed-lines {
    display: grid;
    gap: 14px;
}

.speed-line {
    padding: 16px;
    border-radius: 20px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
}

.speed-bar {
    height: 8px;
    margin-top: 10px;
    overflow: hidden;
    border-radius: 999px;
    background: #e5e7eb;
}

.speed-bar span {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, #2980FE, #7B4EF1);
}

.safety-panel {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 30px;
    padding: 24px;
    box-shadow: 0 20px 52px rgba(31, 41, 55, 0.08);
}

.safety-panel .panel-row {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 0;
    border-bottom: 1px solid #eef2f7;
    color: #4b5563;
}

.safety-panel .panel-row:last-child {
    border-bottom: 0;
}

.process-steps {
    display: grid;
    gap: 16px;
    counter-reset: step;
}

.step-card {
    position: relative;
    padding: 22px;
    border-radius: 24px;
    background: #ffffff;
    border: 1px solid #e5e7eb;
}

.step-number {
    display: inline-grid;
    place-items: center;
    width: 34px;
    height: 34px;
    margin-bottom: 12px;
    border-radius: 12px;
    color: #ffffff;
    background: #2980FE;
    font-weight: 900;
}

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

.risk-card strong {
    display: block;
    margin-bottom: 6px;
    color: #111827;
}

.faq-item details {
    margin: 0;
}

.faq-item summary {
    cursor: pointer;
    color: #111827;
    font-weight: 800;
}

.faq-item p {
    margin-top: 12px;
}

.cta-section {
    overflow: hidden;
    padding: 58px 0;
    background: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    color: #ffffff;
    text-align: center;
}

.cta-section h2,
.cta-section p {
    color: #ffffff;
}

.cta-section p {
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    color: rgba(255,255,255,.88);
}

.page-hero {
    padding: 62px 0 44px;
    background: linear-gradient(180deg, #ffffff 0%, #eef4ff 100%);
    border-bottom: 1px solid #e5e7eb;
}

.page-hero-content {
    max-width: 860px;
}

.page-hero p {
    font-size: 18px;
}

.content-layout {
    display: grid;
    gap: 24px;
}

.article-panel {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 28px;
    padding: 24px;
    box-shadow: 0 16px 40px rgba(31, 41, 55, 0.06);
}

.side-panel {
    display: grid;
    gap: 16px;
    align-content: start;
}

.callout {
    padding: 18px;
    border-radius: 22px;
    background: #f1f6ff;
    border: 1px solid #dceaff;
}

.operation-list {
    margin: 0;
    padding-left: 20px;
    color: #4b5563;
}

.operation-list li {
    margin: 8px 0;
}

.site-footer {
    background: #111827;
    color: #d1d5db;
    padding: 48px 0 24px;
}

.site-footer p,
.site-footer a {
    color: #cbd5e1;
}

.footer-grid {
    display: grid;
    gap: 24px;
}

.footer-grid h3 {
    color: #ffffff;
    font-size: 16px;
}

.footer-grid a {
    display: block;
    margin: 8px 0;
}

.footer-logo span {
    color: #ffffff;
}

.footer-bottom {
    margin-top: 32px;
    padding-top: 18px;
    border-top: 1px solid rgba(255,255,255,.12);
    color: #9ca3af;
    font-size: 14px;
}

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

@media (min-width: 900px) {
    .nav-toggle {
        display: none;
    }

    .site-nav {
        position: static;
        display: flex;
        flex-direction: row;
        align-items: center;
        gap: 4px;
        padding: 0;
        background: transparent;
        border: 0;
        border-radius: 0;
        box-shadow: none;
    }

    .site-nav a {
        padding: 8px 10px;
        font-size: 14px;
    }

    .hero-grid,
    .split-section,
    .vpn-connection-section,
    .high-speed-section,
    .privacy-protection-section,
    .multi-device-section,
    .encryption-protocol-section,
    .global-content,
    .content-layout {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .node-grid {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    .risk-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .policy-grid,
    .page-card-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .float-card {
        display: block;
    }

    .hero-visual {
        min-height: 480px;
    }

    .article-panel {
        padding: 34px;
    }

    .side-panel {
        position: sticky;
        top: 96px;
    }

    .footer-grid {
        grid-template-columns: 1.5fr 1fr 1fr 1fr;
    }
}

@media (min-width: 1100px) {
    .site-nav a {
        padding: 9px 12px;
        font-size: 15px;
    }

    .section {
        padding: 82px 0;
    }

    .vpn-network-hero {
        padding: 92px 0 78px;
    }
}