* {
    box-sizing: border-box;
}

:root {
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --blue: #2980FE;
    --blue-dark: #1768E8;
    --text: #202636;
    --muted: #657086;
    --line: #E7ECF5;
    --soft: #F6F8FC;
    --soft-blue: #F1F6FF;
    --white: #FFFFFF;
    --shadow: 0 18px 55px rgba(33, 58, 112, .10);
    --radius: 28px;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
    background: var(--white);
    color: var(--text);
    line-height: 1.75;
    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: 30;
    background: rgba(255, 255, 255, .92);
    border-bottom: 1px solid rgba(231, 236, 245, .88);
    backdrop-filter: blur(16px);
}

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

.logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    letter-spacing: .02em;
    color: #1E2840;
    white-space: nowrap;
}

.logo img {
    width: 38px;
    height: 38px;
    border-radius: 12px;
    object-fit: cover;
    box-shadow: 0 8px 22px rgba(41, 128, 254, .18);
}

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

.nav-toggle-label {
    width: 42px;
    height: 42px;
    border: 1px solid var(--line);
    border-radius: 14px;
    display: grid;
    place-content: center;
    gap: 5px;
    cursor: pointer;
    background: var(--white);
}

.nav-toggle-label span {
    width: 18px;
    height: 2px;
    border-radius: 4px;
    background: #263047;
    display: block;
}

.site-nav {
    position: absolute;
    left: 16px;
    right: 16px;
    top: 74px;
    display: none;
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: 22px;
    padding: 12px;
    box-shadow: var(--shadow);
}

.site-nav a {
    display: block;
    padding: 11px 14px;
    border-radius: 14px;
    color: #475269;
    font-size: 15px;
}

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

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

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 24px;
    border-radius: 999px;
    background: var(--blue);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 14px 30px rgba(41, 128, 254, .28);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}

.download-btn:hover {
    background: var(--blue-dark);
    transform: translateY(-2px);
    box-shadow: 0 18px 34px rgba(23, 104, 232, .30);
}

.section {
    padding: 64px 0;
}

.section-soft {
    background: var(--soft);
}

.section-head {
    margin-bottom: 26px;
}

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

.eyebrow,
.category-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 12px;
    border-radius: 999px;
    color: var(--blue);
    background: var(--soft-blue);
    font-weight: 800;
    font-size: 13px;
}

h1,
h2,
h3 {
    line-height: 1.22;
    color: #172033;
    margin: 0;
}

h1 {
    font-size: clamp(34px, 8vw, 64px);
    letter-spacing: -.05em;
}

h2 {
    font-size: clamp(28px, 5vw, 44px);
    letter-spacing: -.035em;
}

h3 {
    font-size: 20px;
}

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

.text-link {
    color: var(--blue);
    font-weight: 800;
}

.text-link:hover {
    color: var(--blue-dark);
}

.vpn-saas-hero {
    position: relative;
    padding: 54px 0 72px;
    overflow: hidden;
    background: #F8FAFF;
}

.vpn-saas-hero::before {
    content: "";
    position: absolute;
    inset: 0 0 auto 0;
    height: 78%;
    background: var(--gradient);
    clip-path: polygon(0 0, 100% 0, 100% 78%, 0 100%);
}

.hero-grid {
    position: relative;
    display: grid;
    gap: 36px;
    align-items: center;
}

.hero-copy {
    color: #fff;
}

.hero-copy h1,
.hero-copy p {
    color: #fff;
}

.hero-copy p {
    max-width: 650px;
    opacity: .92;
    font-size: 17px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 14px;
    margin-top: 26px;
}

.hero-note {
    color: rgba(255,255,255,.92);
    font-size: 14px;
}

.security-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 24px;
}

.security-tags span {
    padding: 8px 12px;
    border: 1px solid rgba(255,255,255,.28);
    border-radius: 999px;
    background: rgba(255,255,255,.14);
    color: #fff;
    font-size: 14px;
}

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

.product-frame {
    width: min(420px, 86vw);
    padding: 20px;
    border-radius: 34px;
    background: rgba(255,255,255,.90);
    box-shadow: 0 30px 80px rgba(21, 31, 68, .22);
    transform: rotate(1.5deg);
}

.product-frame img {
    width: 100%;
    border-radius: 24px;
    object-fit: cover;
}

.float-card {
    position: absolute;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    border-radius: 18px;
    background: rgba(255,255,255,.95);
    box-shadow: 0 16px 44px rgba(20, 36, 80, .18);
    color: #283249;
    font-weight: 800;
    font-size: 13px;
}

.float-card::before {
    content: "";
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--blue);
}

.float-card.one { left: 4%; top: 16%; }
.float-card.two { right: 2%; top: 28%; }
.float-card.three { left: 8%; bottom: 20%; }
.float-card.four { right: 6%; bottom: 11%; }

.product-highlights {
    margin-top: -34px;
    position: relative;
    z-index: 2;
}

.highlight-grid {
    display: grid;
    gap: 16px;
}

.highlight-card,
.info-card,
.risk-card,
.faq-item,
.step-card,
.topic-card,
.tip-box,
.value-card {
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: 24px;
    padding: 22px;
    box-shadow: 0 12px 34px rgba(30, 49, 91, .06);
}

.highlight-card .pill,
.info-card .pill {
    display: inline-flex;
    margin-bottom: 12px;
    padding: 5px 10px;
    border-radius: 999px;
    color: var(--blue);
    background: var(--soft-blue);
    font-size: 12px;
    font-weight: 800;
}

.split-panel {
    display: grid;
    gap: 24px;
    align-items: center;
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
}

.split-panel.reverse .visual-card {
    order: -1;
}

.visual-card {
    border-radius: 26px;
    padding: 16px;
    background: linear-gradient(135deg, #F3F7FF 0%, #FFFFFF 65%);
    border: 1px solid var(--line);
}

.visual-card img {
    border-radius: 22px;
    width: 100%;
    object-fit: cover;
}

.feature-list,
.clean-list {
    list-style: none;
    margin: 20px 0 0;
    padding: 0;
    display: grid;
    gap: 10px;
}

.feature-list li,
.clean-list li {
    position: relative;
    padding-left: 22px;
    color: #4A556B;
}

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

.speed-layout,
.nodes-layout,
.device-layout {
    display: grid;
    gap: 20px;
}

.metric-strip {
    display: grid;
    gap: 12px;
    margin-top: 20px;
}

.metric {
    padding: 16px;
    border-radius: 18px;
    background: var(--soft-blue);
    border: 1px solid #DDE9FF;
}

.metric strong {
    display: block;
    color: #172033;
    font-size: 18px;
}

.card-grid,
.privacy-grid,
.policy-grid,
.protocol-grid,
.risk-grid,
.faq-grid,
.topic-grid {
    display: grid;
    gap: 16px;
}

.privacy-protection-section .privacy-panel {
    display: grid;
    gap: 18px;
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 22px;
    box-shadow: var(--shadow);
}

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

.tag-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 18px;
}

.tag-row span {
    padding: 7px 12px;
    border-radius: 999px;
    color: #34405A;
    background: #F0F3FA;
    font-weight: 700;
    font-size: 13px;
}

.no-log-policy-section .policy-grid .info-card,
.encryption-protocol-section .protocol-grid .info-card {
    border-top: 4px solid var(--blue);
}

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

.step-card {
    position: relative;
    padding-left: 78px;
}

.step-num {
    position: absolute;
    left: 22px;
    top: 22px;
    width: 38px;
    height: 38px;
    border-radius: 14px;
    display: grid;
    place-items: center;
    color: #fff;
    background: var(--gradient);
    font-weight: 900;
}

.risk-card {
    border-left: 4px solid var(--blue);
}

.risk-card strong {
    display: block;
    color: #172033;
    margin-bottom: 4px;
}

.faq-item h3,
.faq-item summary {
    color: #172033;
    font-weight: 800;
    font-size: 18px;
}

.faq-item details,
.faq-item summary {
    cursor: pointer;
}

.cta-section {
    padding: 68px 0;
}

.cta-box {
    position: relative;
    overflow: hidden;
    padding: 34px 24px;
    border-radius: 32px;
    background: var(--gradient);
    text-align: center;
    color: #fff;
    box-shadow: 0 22px 70px rgba(74, 76, 206, .24);
}

.cta-box h2,
.cta-box p {
    color: #fff;
}

.cta-box p {
    max-width: 680px;
    margin: 12px auto 0;
    opacity: .92;
}

.cta-box .download-btn {
    margin-top: 24px;
}

.page-hero {
    padding: 58px 0 34px;
    background: linear-gradient(180deg, #F6F8FF 0%, #FFFFFF 100%);
}

.page-hero-inner {
    max-width: 820px;
}

.page-hero h1 {
    margin-top: 14px;
}

.page-hero p {
    font-size: 17px;
}

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

.article-main {
    display: grid;
    gap: 18px;
}

.article-card {
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: 26px;
    padding: 24px;
    box-shadow: 0 14px 45px rgba(30, 49, 91, .06);
}

.article-card h2 {
    font-size: 28px;
}

.aside-panel {
    background: var(--soft-blue);
    border: 1px solid #DCE9FF;
    border-radius: 26px;
    padding: 22px;
    align-self: start;
}

.aside-panel a {
    display: block;
    padding: 10px 0;
    color: var(--blue);
    font-weight: 800;
}

.check-grid {
    display: grid;
    gap: 12px;
    margin-top: 16px;
}

.check-item {
    padding: 14px;
    border-radius: 18px;
    background: var(--soft);
    border: 1px solid var(--line);
}

.download-page .download-card {
    text-align: center;
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: 30px;
    padding: 34px 24px;
    box-shadow: var(--shadow);
}

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

.steps-list {
    display: grid;
    gap: 14px;
    margin-top: 18px;
}

.steps-list .step-line {
    display: flex;
    gap: 12px;
    align-items: flex-start;
    padding: 16px;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: #fff;
}

.steps-list b {
    flex: 0 0 32px;
    width: 32px;
    height: 32px;
    display: grid;
    place-items: center;
    border-radius: 12px;
    background: var(--soft-blue);
    color: var(--blue);
}

.site-footer {
    background: #101828;
    color: #C8D0E0;
    padding: 48px 0 22px;
}

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

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

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

.site-footer p {
    color: #A9B4C8;
}

.site-footer a {
    display: block;
    color: #C8D0E0;
    padding: 5px 0;
}

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

.footer-bottom {
    margin-top: 30px;
    padding-top: 18px;
    border-top: 1px solid rgba(255,255,255,.12);
    color: #9EA9BC;
    font-size: 14px;
}

@media (min-width: 700px) {
    .highlight-grid,
    .privacy-grid,
    .policy-grid,
    .protocol-grid,
    .risk-grid,
    .topic-grid,
    .check-grid,
    .faq-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

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

    .process-steps {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (min-width: 980px) {
    .nav-toggle-label {
        display: none;
    }

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

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

    .vpn-saas-hero {
        padding: 76px 0 116px;
    }

    .hero-grid {
        grid-template-columns: 1.05fr .95fr;
        gap: 54px;
    }

    .product-highlights {
        margin-top: -74px;
    }

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

    .split-panel,
    .speed-layout,
    .nodes-layout,
    .device-layout,
    .privacy-protection-section .privacy-panel {
        grid-template-columns: 1fr 1fr;
    }

    .split-panel {
        padding: 34px;
    }

    .split-panel.reverse .visual-card {
        order: 2;
    }

    .policy-grid,
    .protocol-grid,
    .risk-grid,
    .footer-grid {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }

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

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

    .article-layout {
        grid-template-columns: minmax(0, 1fr) 310px;
        align-items: start;
    }

    .section {
        padding: 86px 0;
    }

    .cta-box {
        padding: 52px;
    }
}

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

    .hero-actions {
        align-items: stretch;
        flex-direction: column;
    }

    .download-btn {
        width: 100%;
    }

    .float-card {
        font-size: 12px;
        padding: 8px 10px;
    }

    .float-card.one { left: 0; top: 10%; }
    .float-card.two { right: 0; top: 23%; }
    .float-card.three { left: 0; bottom: 18%; }
    .float-card.four { right: 0; bottom: 5%; }

    .step-card {
        padding-left: 22px;
        padding-top: 70px;
    }
}