:root {
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --blue: #2980FE;
    --blue-dark: #1768E8;
    --text: #1f2937;
    --muted: #64748b;
    --light: #f5f7fb;
    --line: #e5eaf3;
    --white: #ffffff;
    --dark: #111827;
    --radius-xl: 34px;
    --radius-lg: 26px;
    --radius-md: 18px;
    --shadow: 0 18px 55px rgba(30, 60, 120, 0.10);
    --soft-shadow: 0 10px 30px rgba(30, 60, 120, 0.08);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background: #f7f9fd;
    line-height: 1.7;
    overflow-x: hidden;
}

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

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

p {
    margin: 0 0 16px;
    color: var(--muted);
}

h1, h2, h3 {
    color: var(--dark);
    line-height: 1.18;
    margin: 0 0 16px;
}

h1 {
    font-size: clamp(2.1rem, 8vw, 4.8rem);
    letter-spacing: -0.05em;
}

h2 {
    font-size: clamp(1.7rem, 5vw, 3rem);
    letter-spacing: -0.035em;
}

h3 {
    font-size: 1.1rem;
}

ul, ol {
    margin: 0;
    padding-left: 20px;
    color: var(--muted);
}

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

.narrow-container {
    width: min(920px, calc(100% - 32px));
    margin: 0 auto;
}

.section {
    padding: 68px 0;
}

.section-soft {
    background: #eef4ff;
}

.section-kicker,
.badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 12px;
    border-radius: 999px;
    color: var(--blue);
    background: rgba(41, 128, 254, 0.10);
    font-size: 0.86rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
}

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

.logo,
.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    color: #16203a;
    white-space: nowrap;
}

.logo img,
.footer-logo img {
    width: 42px;
    height: 42px;
    border-radius: 14px;
    object-fit: cover;
    box-shadow: 0 8px 20px rgba(53, 88, 242, 0.18);
}

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

.main-nav a {
    padding: 10px 12px;
    border-radius: 12px;
    color: #475569;
    font-weight: 650;
    font-size: 0.95rem;
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--blue);
    background: rgba(41, 128, 254, 0.08);
}

.nav-toggle {
    display: none;
}

.nav-toggle-label {
    width: 42px;
    height: 42px;
    border-radius: 14px;
    border: 1px solid var(--line);
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    cursor: pointer;
    background: #fff;
}

.nav-toggle-label span {
    width: 18px;
    height: 2px;
    background: #1f2937;
    border-radius: 99px;
}

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

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 24px;
    border-radius: 999px;
    background: var(--blue);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 14px 26px rgba(41, 128, 254, 0.24);
    transition: transform 0.2s ease, background 0.2s ease, box-shadow 0.2s ease;
}

.download-btn:hover {
    background: var(--blue-dark);
    transform: translateY(-2px);
    box-shadow: 0 18px 34px rgba(23, 104, 232, 0.28);
}

.vpn-saas-hero {
    position: relative;
    padding: 56px 0 72px;
    overflow: hidden;
    background: #f8fbff;
}

.vpn-saas-hero::before {
    content: "";
    position: absolute;
    inset: 0 0 auto 0;
    height: 76%;
    background: var(--gradient);
    clip-path: polygon(0 0, 100% 0, 100% 82%, 0 100%);
}

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

.hero-copy {
    color: #fff;
}

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

.hero-copy p {
    font-size: 1.05rem;
    opacity: 0.92;
    max-width: 650px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    align-items: center;
    margin: 26px 0;
}

.hero-note {
    color: rgba(255, 255, 255, 0.86);
    font-size: 0.92rem;
}

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

.hero-tags span,
.floating-tags span,
.tag-row span {
    display: inline-flex;
    padding: 7px 11px;
    border-radius: 999px;
    font-size: 0.86rem;
    font-weight: 700;
}

.hero-tags span {
    color: #fff;
    background: rgba(255, 255, 255, 0.18);
    border: 1px solid rgba(255, 255, 255, 0.22);
}

.hero-visual {
    position: relative;
    background: rgba(255, 255, 255, 0.18);
    border: 1px solid rgba(255, 255, 255, 0.24);
    border-radius: var(--radius-xl);
    padding: 18px;
    box-shadow: 0 24px 70px rgba(24, 38, 98, 0.20);
}

.hero-visual::after {
    content: "";
    position: absolute;
    inset: 9% -8% -8% 20%;
    background: rgba(255, 255, 255, 0.18);
    border-radius: 48px;
    z-index: -1;
}

.hero-device {
    border-radius: 28px;
    background: #fff;
    padding: 14px;
}

.floating-card {
    position: absolute;
    display: none;
    padding: 10px 14px;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.94);
    color: #1f2937;
    box-shadow: 0 16px 35px rgba(15, 23, 42, 0.16);
    font-weight: 800;
    font-size: 0.9rem;
}

.floating-card.one { left: -8px; top: 18%; }
.floating-card.two { right: -10px; top: 26%; }
.floating-card.three { left: 8%; bottom: 5%; }
.floating-card.four { right: 6%; bottom: 12%; }

.product-highlights {
    margin-top: -28px;
    position: relative;
    z-index: 3;
}

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

.highlight-card,
.info-card,
.risk-card,
.faq-item,
.policy-card,
.related-card {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    padding: 22px;
    box-shadow: var(--soft-shadow);
}

.highlight-card .mini-label,
.info-card .mini-label {
    display: inline-flex;
    margin-bottom: 12px;
    padding: 5px 10px;
    border-radius: 999px;
    color: var(--blue);
    background: rgba(41, 128, 254, 0.1);
    font-weight: 800;
    font-size: 0.78rem;
}

.text-link {
    display: inline-flex;
    align-items: center;
    color: var(--blue);
    font-weight: 800;
    margin-top: 4px;
}

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

.feature-panel,
.visual-panel,
.privacy-protection-section,
.no-log-policy-section,
.cta-section,
.page-hero,
.article-shell {
    border-radius: var(--radius-xl);
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.feature-panel,
.privacy-protection-section,
.no-log-policy-section,
.article-shell {
    padding: 28px;
}

.visual-panel {
    padding: 18px;
    overflow: hidden;
    background: linear-gradient(180deg, #ffffff 0%, #f1f6ff 100%);
}

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

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

.feature-list li {
    position: relative;
    padding-left: 28px;
    color: #475569;
}

.feature-list li::before {
    content: "";
    position: absolute;
    left: 0;
    top: 10px;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--blue);
    box-shadow: 0 0 0 5px rgba(41, 128, 254, 0.12);
}

.high-speed-section {
    padding: 28px;
    border-radius: var(--radius-xl);
    background: #eef4ff;
}

.speed-metrics,
.node-tips,
.protocol-stack {
    display: grid;
    gap: 14px;
    margin-top: 20px;
}

.metric,
.node-tip,
.protocol-item {
    padding: 18px;
    border-radius: 20px;
    background: #fff;
    border: 1px solid var(--line);
}

.metric strong,
.node-tip strong,
.protocol-item strong {
    display: block;
    color: #172033;
    margin-bottom: 4px;
}

.privacy-protection-section {
    background: linear-gradient(180deg, #fff 0%, #f6f9ff 100%);
}

.privacy-layout {
    display: grid;
    gap: 24px;
    align-items: center;
}

.privacy-cards {
    display: grid;
    gap: 14px;
    margin-top: 18px;
}

.privacy-cards div {
    padding: 18px;
    border-radius: 22px;
    background: #fff;
    border: 1px solid var(--line);
}

.no-log-policy-section {
    background: #18213a;
}

.no-log-policy-section h2,
.no-log-policy-section h3 {
    color: #fff;
}

.no-log-policy-section p {
    color: #cbd5e1;
}

.policy-card {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.14);
    box-shadow: none;
}

.multi-device-section .device-card {
    padding: 18px;
    border-radius: 24px;
    background: #fff;
    border: 1px solid var(--line);
    display: grid;
    gap: 10px;
}

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

.encryption-protocol-section {
    padding: 28px;
    border-radius: var(--radius-xl);
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

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

.step-card {
    position: relative;
    padding: 22px;
    border-radius: 24px;
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: var(--soft-shadow);
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border-radius: 14px;
    background: var(--blue);
    color: #fff;
    font-weight: 900;
    margin-bottom: 12px;
}

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

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

.faq-item h3 {
    font-size: 1rem;
    margin-bottom: 8px;
}

.cta-section {
    padding: 38px 24px;
    text-align: center;
    color: #fff;
    background: var(--gradient);
    border: none;
    overflow: hidden;
    position: relative;
}

.cta-section::before {
    content: "";
    position: absolute;
    width: 220px;
    height: 220px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.18);
    right: -80px;
    top: -80px;
}

.cta-section h2,
.cta-section p {
    position: relative;
    color: #fff;
}

.cta-section .download-btn {
    position: relative;
    margin-top: 10px;
}

.page-hero {
    margin-top: 28px;
    padding: 34px 24px;
    background: linear-gradient(135deg, #fff 0%, #eef4ff 100%);
}

.page-hero p {
    max-width: 760px;
    font-size: 1.03rem;
}

.article-shell {
    margin-top: 24px;
}

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

.article-main > * + * {
    margin-top: 18px;
}

.article-main section {
    padding: 22px;
    border-radius: 24px;
    background: #fff;
    border: 1px solid var(--line);
}

.sidebar-panel {
    padding: 22px;
    border-radius: 24px;
    background: #f8fbff;
    border: 1px solid var(--line);
    height: fit-content;
}

.check-list {
    display: grid;
    gap: 12px;
    padding: 0;
    list-style: none;
}

.check-list li {
    padding: 14px 14px 14px 40px;
    border-radius: 16px;
    background: #f8fbff;
    border: 1px solid var(--line);
    position: relative;
    color: #475569;
}

.check-list li::before {
    content: "✓";
    position: absolute;
    left: 14px;
    top: 13px;
    width: 18px;
    height: 18px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: rgba(41, 128, 254, 0.12);
    color: var(--blue);
    font-size: 0.78rem;
    font-weight: 900;
}

.download-card {
    margin-top: 24px;
    padding: 24px;
    border-radius: 26px;
    background: var(--gradient);
    color: #fff;
    text-align: center;
}

.download-card h2,
.download-card p {
    color: #fff;
}

.download-flow {
    display: grid;
    gap: 14px;
    margin-top: 22px;
}

.download-flow div {
    padding: 18px;
    border-radius: 20px;
    background: #fff;
    border: 1px solid var(--line);
}

.download-flow strong {
    display: block;
    color: #172033;
}

.site-footer {
    margin-top: 72px;
    padding: 52px 0 24px;
    background: #101827;
    color: #d7dee9;
}

.site-footer p,
.site-footer a,
.site-footer span {
    color: #b9c4d4;
}

.site-footer h2 {
    color: #fff;
    font-size: 1rem;
    margin-bottom: 12px;
}

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

.footer-grid a:not(.footer-logo) {
    display: block;
    margin: 8px 0;
}

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

.footer-bottom {
    margin-top: 28px;
    padding-top: 22px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    font-size: 0.92rem;
}

@media (min-width: 720px) {
    .highlight-grid,
    .card-grid,
    .risk-grid,
    .faq-grid,
    .policy-grid,
    .related-grid,
    .device-grid,
    .privacy-cards,
    .download-flow {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

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

    .speed-metrics,
    .node-tips,
    .protocol-stack {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

@media (min-width: 980px) {
    .section {
        padding: 88px 0;
    }

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

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

    .hero-inner {
        grid-template-columns: 1.03fr 0.97fr;
        gap: 56px;
    }

    .vpn-saas-hero {
        padding: 88px 0 110px;
    }

    .floating-card {
        display: block;
    }

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

    .feature-split,
    .vpn-connection-section,
    .global-nodes-section,
    .multi-device-section,
    .encryption-protocol-section,
    .privacy-layout {
        grid-template-columns: 1fr 1fr;
    }

    .high-speed-section {
        grid-template-columns: 0.95fr 1.05fr;
    }

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

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

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

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

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

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

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

    .download-btn {
        width: 100%;
    }

    .feature-panel,
    .privacy-protection-section,
    .no-log-policy-section,
    .article-shell {
        padding: 22px;
    }
}