* {
    box-sizing: border-box;
}

:root {
    --primary: #2980FE;
    --primary-dark: #1768E8;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --text: #1f2937;
    --muted: #667085;
    --light: #f5f7fb;
    --line: #e6eaf2;
    --card: #ffffff;
    --soft-blue: #edf5ff;
    --shadow: 0 18px 45px rgba(31, 41, 55, .08);
    --radius: 24px;
}

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: #ffffff;
    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;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, .95);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--line);
}

.header-inner {
    min-height: 70px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    color: #111827;
    white-space: nowrap;
}

.logo img {
    width: 40px;
    height: 40px;
    object-fit: cover;
    border-radius: 12px;
}

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

.nav-toggle-label {
    width: 44px;
    height: 44px;
    display: grid;
    place-content: center;
    gap: 5px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background: #fff;
}

.nav-toggle-label span {
    width: 20px;
    height: 2px;
    border-radius: 999px;
    background: #1f2937;
}

.site-nav {
    position: absolute;
    left: 16px;
    right: 16px;
    top: 72px;
    display: none;
    flex-direction: column;
    padding: 14px;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 20px;
    box-shadow: var(--shadow);
}

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

.site-nav a {
    padding: 11px 12px;
    border-radius: 12px;
    color: #344054;
    font-size: 15px;
}

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

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 24px;
    border-radius: 999px;
    background: var(--primary);
    color: #fff;
    font-weight: 700;
    border: 0;
    box-shadow: 0 12px 30px rgba(41, 128, 254, .28);
    transition: background .2s ease, transform .2s ease, box-shadow .2s ease;
}

.download-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: 0 16px 34px rgba(23, 104, 232, .32);
}

.vpn-network-hero {
    position: relative;
    overflow: hidden;
    background: var(--gradient);
    color: #fff;
    padding: 68px 0 56px;
}

.vpn-network-hero::before,
.vpn-network-hero::after {
    content: "";
    position: absolute;
    pointer-events: none;
}

.vpn-network-hero::before {
    inset: 0;
    background-image: radial-gradient(circle at 18% 18%, rgba(255, 255, 255, .26) 0 2px, transparent 3px), radial-gradient(circle at 70% 38%, rgba(255, 255, 255, .26) 0 2px, transparent 3px), radial-gradient(circle at 48% 78%, rgba(255, 255, 255, .18) 0 2px, transparent 3px), linear-gradient(135deg, rgba(255,255,255,.16) 1px, transparent 1px);
    background-size: 190px 160px, 220px 180px, 210px 170px, 80px 80px;
    opacity: .55;
}

.vpn-network-hero::after {
    width: 430px;
    height: 430px;
    right: -160px;
    top: -120px;
    border-radius: 50%;
    background: rgba(255, 255, 255, .18);
    filter: blur(10px);
}

.hero-grid {
    position: relative;
    z-index: 1;
    display: grid;
    gap: 34px;
    align-items: center;
}

.hero-content h1 {
    margin: 0 0 18px;
    font-size: clamp(34px, 8vw, 62px);
    line-height: 1.08;
    letter-spacing: -.04em;
}

.hero-content p {
    max-width: 640px;
    margin: 0 0 24px;
    color: rgba(255, 255, 255, .88);
    font-size: 17px;
}

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

.hero-tags span,
.status-tags span,
.inline-tags span,
.category-badge {
    display: inline-flex;
    align-items: center;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
}

.hero-tags span {
    padding: 8px 12px;
    background: rgba(255, 255, 255, .16);
    border: 1px solid rgba(255, 255, 255, .24);
}

.hero-art {
    position: relative;
    padding: 16px;
}

.hero-art::before {
    content: "";
    position: absolute;
    inset: 6% 3%;
    background: rgba(255, 255, 255, .15);
    border: 1px solid rgba(255, 255, 255, .22);
    border-radius: 32px;
    transform: rotate(-3deg);
}

.hero-art img {
    position: relative;
    z-index: 1;
    border-radius: 30px;
    box-shadow: 0 30px 70px rgba(18, 30, 76, .25);
}

.floating-card {
    position: absolute;
    z-index: 2;
    display: none;
    padding: 10px 14px;
    border-radius: 16px;
    background: rgba(255, 255, 255, .94);
    color: #1f2937;
    font-weight: 800;
    box-shadow: var(--shadow);
    font-size: 13px;
}

.floating-card.one { top: 8%; left: 0; }
.floating-card.two { right: 0; top: 26%; }
.floating-card.three { left: 8%; bottom: 14%; }
.floating-card.four { right: 10%; bottom: 2%; }

.section {
    padding: 64px 0;
}

.section-soft {
    background: linear-gradient(180deg, #f7faff 0%, #ffffff 100%);
}

.section-title {
    max-width: 760px;
    margin: 0 auto 28px;
    text-align: center;
}

.section-title.left {
    text-align: left;
    margin-left: 0;
}

.section-title h2,
.page-hero h1,
.article-body h2,
.about-block h2 {
    margin: 0 0 12px;
    color: #101828;
    line-height: 1.2;
}

.section-title h2 {
    font-size: clamp(26px, 4vw, 40px);
}

.section-title p,
.muted {
    color: var(--muted);
}

.node-overview {
    margin-top: -28px;
    position: relative;
    z-index: 2;
}

.node-grid,
.feature-grid,
.policy-grid,
.risk-grid,
.faq-grid,
.related-grid,
.step-grid {
    display: grid;
    gap: 18px;
}

.node-card,
.feature-card,
.policy-card,
.risk-card,
.faq-item,
.step-card,
.info-card,
.side-panel,
.article-body,
.download-panel,
.safety-panel,
.about-card {
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: 0 12px 32px rgba(31, 41, 55, .05);
}

.node-card,
.feature-card,
.policy-card,
.risk-card,
.faq-item,
.step-card,
.info-card,
.about-card {
    padding: 22px;
}

.node-card .tag,
.info-card .tag {
    display: inline-flex;
    margin-bottom: 12px;
    padding: 4px 10px;
    border-radius: 999px;
    background: var(--soft-blue);
    color: var(--primary);
    font-size: 13px;
    font-weight: 800;
}

.node-card h3,
.feature-card h3,
.policy-card h3,
.risk-card h3,
.step-card h3,
.info-card h3 {
    margin: 0 0 8px;
    color: #101828;
}

.card-link,
.text-link {
    display: inline-flex;
    margin-top: 12px;
    color: var(--primary);
    font-weight: 800;
}

.split-section {
    display: grid;
    gap: 28px;
    align-items: center;
}

.image-panel {
    position: relative;
    padding: 14px;
    border-radius: 32px;
    background: linear-gradient(145deg, #eef5ff, #ffffff);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.image-panel img {
    border-radius: 24px;
}

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

.bullet-list li,
.check-list li,
.number-list li {
    position: relative;
    padding-left: 26px;
    color: #344054;
}

.bullet-list li::before,
.check-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: .72em;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--primary);
}

.global-nodes-section {
    position: relative;
    overflow: hidden;
    border-radius: 32px;
    padding: 34px;
    background: linear-gradient(135deg, #f0f6ff, #ffffff);
    border: 1px solid var(--line);
}

.global-nodes-section::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image: radial-gradient(circle at 25% 30%, rgba(41,128,254,.22) 0 3px, transparent 4px), radial-gradient(circle at 68% 42%, rgba(123,78,241,.22) 0 3px, transparent 4px), radial-gradient(circle at 45% 76%, rgba(184,77,218,.2) 0 3px, transparent 4px), linear-gradient(120deg, transparent 0 42%, rgba(41,128,254,.12) 43%, transparent 44% 100%);
    opacity: .9;
}

.global-nodes-section > * {
    position: relative;
    z-index: 1;
}

.speed-card {
    border-left: 5px solid var(--primary);
}

.privacy-protection-section,
.encryption-protocol-section {
    display: grid;
    gap: 22px;
}

.safety-panel {
    padding: 24px;
    background: linear-gradient(180deg, #ffffff, #f7fbff);
}

.inline-tags span,
.status-tags span {
    padding: 7px 11px;
    background: var(--soft-blue);
    color: var(--primary);
}

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

.step-number {
    width: 36px;
    height: 36px;
    display: inline-grid;
    place-items: center;
    margin-bottom: 12px;
    border-radius: 12px;
    background: var(--primary);
    color: #fff;
    font-weight: 900;
}

.risk-card {
    border-left: 5px solid var(--primary);
}

.risk-card strong {
    display: block;
    margin-top: 8px;
    color: #101828;
}

.faq-item details {
    margin: 0;
}

.faq-item summary {
    cursor: pointer;
    font-weight: 800;
    color: #101828;
}

.faq-item p {
    margin: 12px 0 0;
    color: var(--muted);
}

.cta-section {
    padding: 58px 0;
    background: var(--gradient);
    color: #fff;
    text-align: center;
}

.cta-section h2 {
    margin: 0 0 12px;
    font-size: clamp(26px, 5vw, 42px);
}

.cta-section p {
    max-width: 680px;
    margin: 0 auto 22px;
    color: rgba(255,255,255,.86);
}

.page-hero {
    padding: 54px 0;
    background: linear-gradient(180deg, #f2f7ff 0%, #ffffff 100%);
}

.compact-hero .container {
    max-width: 880px;
}

.category-badge {
    padding: 7px 12px;
    margin-bottom: 14px;
    background: var(--soft-blue);
    color: var(--primary);
}

.page-hero h1 {
    font-size: clamp(30px, 6vw, 50px);
}

.page-hero p {
    max-width: 780px;
    color: var(--muted);
    margin: 0;
    font-size: 17px;
}

.article-layout {
    display: grid;
    gap: 24px;
    padding: 48px 0 68px;
}

.article-body {
    padding: 26px;
}

.article-body p {
    color: #344054;
}

.article-body .download-btn {
    margin-top: 18px;
}

.info-panel {
    margin: 24px 0;
    padding: 20px;
    border-radius: 22px;
    background: #f7faff;
    border: 1px solid var(--line);
}

.info-panel h2,
.info-panel h3 {
    margin-top: 0;
}

.side-panel {
    padding: 22px;
    align-self: start;
}

.side-panel h3 {
    margin-top: 0;
}

.side-panel a {
    display: block;
    padding: 10px 0;
    border-bottom: 1px solid var(--line);
    color: #344054;
}

.side-panel a:hover {
    color: var(--primary);
}

.download-panel {
    padding: 28px;
    text-align: center;
}

.download-steps {
    counter-reset: step;
    display: grid;
    gap: 14px;
    padding: 0;
    margin: 24px 0;
    list-style: none;
}

.download-steps li {
    counter-increment: step;
    padding: 16px 18px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: #fff;
    text-align: left;
}

.download-steps li::before {
    content: counter(step);
    display: inline-grid;
    place-items: center;
    width: 30px;
    height: 30px;
    margin-right: 10px;
    border-radius: 10px;
    background: var(--primary);
    color: #fff;
    font-weight: 900;
}

.about-grid {
    display: grid;
    gap: 18px;
}

.site-footer {
    background: #101828;
    color: #d0d5dd;
    padding: 44px 0 22px;
}

.footer-grid {
    display: grid;
    gap: 26px;
}

.footer-brand {
    color: #fff;
    font-size: 22px;
    font-weight: 900;
    margin-bottom: 10px;
}

.site-footer h3 {
    color: #fff;
    margin: 0 0 12px;
    font-size: 16px;
}

.site-footer a {
    display: block;
    color: #d0d5dd;
    padding: 5px 0;
}

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

.footer-bottom {
    margin-top: 28px;
    padding-top: 18px;
    border-top: 1px solid rgba(255,255,255,.1);
    color: #98a2b3;
    font-size: 14px;
}

@media (min-width: 700px) {
    .node-grid,
    .policy-grid,
    .risk-grid,
    .faq-grid,
    .related-grid,
    .step-grid,
    .about-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .download-steps {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 960px) {
    .nav-toggle-label {
        display: none;
    }

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

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

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

    .hero-grid,
    .split-section,
    .privacy-protection-section,
    .encryption-protocol-section {
        grid-template-columns: 1.05fr .95fr;
    }

    .hero-art {
        padding: 24px;
    }

    .floating-card {
        display: block;
    }

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

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

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

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

    .article-layout {
        grid-template-columns: minmax(0, 1fr) 300px;
    }

    .footer-grid {
        grid-template-columns: 1.4fr repeat(3, 1fr);
    }

    .section {
        padding: 82px 0;
    }
}