:root {
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --blue: #2980FE;
    --blue-hover: #1768E8;
    --text: #1f2937;
    --muted: #667085;
    --light: #f5f7fb;
    --lighter: #eef5ff;
    --line: #e5e7eb;
    --white: #ffffff;
    --shadow: 0 18px 50px rgba(31, 41, 55, .09);
    --radius-xl: 30px;
    --radius-lg: 24px;
    --radius-md: 18px;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--text);
    background: #fbfcff;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
    line-height: 1.75;
    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 {
    line-height: 1.25;
    margin: 0 0 16px;
    color: #111827;
    letter-spacing: -.02em;
}

ul, ol {
    padding-left: 20px;
    margin: 0;
}

li {
    margin: 8px 0;
    color: var(--muted);
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, .92);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(229, 231, 235, .9);
}

.header-inner {
    width: min(1160px, calc(100% - 32px));
    margin: 0 auto;
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}

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

.brand-logo {
    width: 42px;
    height: 42px;
    border-radius: 14px;
    object-fit: cover;
    box-shadow: 0 10px 24px rgba(41, 128, 254, .18);
}

.brand-text {
    font-size: 18px;
}

.site-nav {
    display: none;
    flex-direction: column;
    position: absolute;
    left: 16px;
    right: 16px;
    top: 72px;
    padding: 14px;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 22px;
    box-shadow: var(--shadow);
}

.site-nav a {
    padding: 10px 12px;
    border-radius: 14px;
    color: #4b5563;
    font-size: 15px;
}

.site-nav a:hover,
.site-nav a.active {
    color: var(--blue);
    background: #eef5ff;
}

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

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

.nav-toggle-label span {
    width: 18px;
    height: 2px;
    border-radius: 2px;
    background: #111827;
}

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

.container {
    width: min(1160px, calc(100% - 32px));
    margin: 0 auto;
}

.narrow-container {
    width: min(900px, calc(100% - 32px));
    margin: 0 auto;
}

.section {
    padding: 64px 0;
}

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

.eyebrow,
.category-badge,
.pill {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--blue);
    background: #eef5ff;
    border: 1px solid #d9e8ff;
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 22px;
    border-radius: 999px;
    background: var(--blue);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 14px 30px rgba(41, 128, 254, .28);
    transition: transform .18s ease, background .18s ease, box-shadow .18s ease;
}

.download-btn:hover {
    background: var(--blue-hover);
    transform: translateY(-2px);
    box-shadow: 0 18px 36px rgba(23, 104, 232, .32);
}

.text-link {
    color: var(--blue);
    font-weight: 700;
}

.vpn-lab-hero {
    background: var(--gradient);
    color: #fff;
    overflow: hidden;
    position: relative;
}

.vpn-lab-hero::before,
.vpn-lab-hero::after {
    content: "";
    position: absolute;
    border-radius: 999px;
    background: rgba(255,255,255,.16);
    filter: blur(1px);
}

.vpn-lab-hero::before {
    width: 280px;
    height: 280px;
    top: -90px;
    right: -90px;
}

.vpn-lab-hero::after {
    width: 180px;
    height: 180px;
    left: -70px;
    bottom: 80px;
}

.hero-inner {
    position: relative;
    z-index: 1;
    width: min(1160px, calc(100% - 32px));
    margin: 0 auto;
    padding: 74px 0;
    display: grid;
    grid-template-columns: 1fr;
    gap: 34px;
    align-items: center;
}

.hero-copy h1 {
    color: #fff;
    font-size: clamp(34px, 9vw, 62px);
    max-width: 760px;
}

.hero-copy p {
    color: rgba(255,255,255,.88);
    font-size: 17px;
    max-width: 680px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
    margin: 26px 0 22px;
}

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

.hero-tags span,
.status-tags span,
.inline-tags span {
    display: inline-flex;
    padding: 7px 11px;
    border-radius: 999px;
    background: rgba(255,255,255,.16);
    color: rgba(255,255,255,.95);
    font-size: 13px;
    border: 1px solid rgba(255,255,255,.22);
}

.hero-visual {
    position: relative;
    min-height: 330px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-device-card {
    width: min(440px, 100%);
    padding: 24px;
    border-radius: 34px;
    background: rgba(255,255,255,.18);
    border: 1px solid rgba(255,255,255,.25);
    box-shadow: 0 30px 70px rgba(10, 18, 56, .22);
    backdrop-filter: blur(16px);
}

.hero-device-card img {
    width: 100%;
    border-radius: 26px;
    background: #fff;
}

.float-card {
    position: absolute;
    background: rgba(255,255,255,.95);
    color: #111827;
    border-radius: 18px;
    padding: 10px 13px;
    font-size: 13px;
    font-weight: 800;
    box-shadow: 0 16px 40px rgba(10, 18, 56, .18);
}

.float-card.one { top: 8%; left: 0; }
.float-card.two { top: 18%; right: 0; }
.float-card.three { bottom: 20%; left: 3%; }
.float-card.four { bottom: 8%; right: 4%; }

.privacy-summary {
    margin-top: -42px;
    position: relative;
    z-index: 2;
}

.summary-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.summary-card,
.security-card,
.info-card,
.risk-card,
.faq-item,
.step-card,
.notice-card {
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    box-shadow: 0 10px 30px rgba(31, 41, 55, .05);
}

.summary-card {
    padding: 24px;
    position: relative;
    overflow: hidden;
}

.summary-card::before {
    content: "";
    width: 42px;
    height: 4px;
    border-radius: 999px;
    background: var(--blue);
    display: block;
    margin-bottom: 18px;
}

.summary-card h3 {
    font-size: 20px;
}

.module-grid,
.split-section,
.vpn-connection-section,
.global-nodes-section,
.high-speed-section,
.multi-device-section {
    display: grid;
    grid-template-columns: 1fr;
    gap: 28px;
    align-items: center;
}

.module-copy h2,
.section-title h2 {
    font-size: clamp(28px, 6vw, 42px);
}

.module-copy p {
    font-size: 16px;
}

.module-media {
    border-radius: var(--radius-xl);
    padding: 18px;
    background: linear-gradient(180deg, #ffffff, #f5f8ff);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.module-media img {
    border-radius: 24px;
    margin: 0 auto;
}

.feature-list {
    display: grid;
    grid-template-columns: 1fr;
    gap: 12px;
    margin: 20px 0;
}

.feature-list div,
.check-item {
    padding: 14px 16px;
    background: #fff;
    border: 1px solid var(--line);
    border-left: 4px solid var(--blue);
    border-radius: 16px;
    color: var(--muted);
}

.privacy-protection-section {
    background: #f6f8fc;
}

.privacy-panel {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.security-card {
    padding: 24px;
}

.security-card h3 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 19px;
}

.security-card h3::before {
    content: "";
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--blue);
    box-shadow: 0 0 0 6px #e5f0ff;
}

.no-log-policy-section .policy-grid,
.encryption-protocol-section .tech-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.policy-grid .info-card,
.tech-grid .info-card {
    padding: 22px;
}

.high-speed-section {
    background: #f1f6ff;
    border-top: 1px solid #e5efff;
    border-bottom: 1px solid #e5efff;
}

.device-showcase {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.device-card {
    padding: 20px;
    border-radius: 22px;
    background: #fff;
    border: 1px solid var(--line);
}

.encryption-protocol-section {
    background: #fbfcff;
}

.tech-panel {
    padding: 24px;
    border-radius: var(--radius-xl);
    background:
        linear-gradient(90deg, rgba(53,88,242,.08), rgba(184,77,218,.08)),
        #fff;
    border: 1px solid #dbe7ff;
}

.process-steps {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.step-card {
    padding: 22px;
    position: relative;
}

.step-number {
    display: inline-flex;
    width: 34px;
    height: 34px;
    border-radius: 12px;
    align-items: center;
    justify-content: center;
    background: var(--blue);
    color: #fff;
    font-weight: 800;
    margin-bottom: 12px;
}

.risk-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}

.risk-card {
    padding: 20px;
    border-left: 4px solid var(--blue);
}

.risk-card strong {
    display: block;
    margin-bottom: 8px;
    color: #111827;
}

.risk-card em {
    font-style: normal;
    display: block;
    color: var(--muted);
    margin-bottom: 10px;
}

.faq-list {
    display: grid;
    gap: 14px;
}

.faq-item {
    padding: 22px;
}

.faq-item h3 {
    font-size: 18px;
    margin-bottom: 8px;
}

.cta-section {
    padding: 66px 0;
    background: var(--gradient);
    color: #fff;
    text-align: center;
}

.cta-section h2 {
    color: #fff;
    font-size: clamp(28px, 7vw, 42px);
}

.cta-section p {
    color: rgba(255,255,255,.88);
    max-width: 720px;
    margin: 0 auto 24px;
}

.page-hero {
    padding: 64px 0 34px;
    background: linear-gradient(180deg, #eef5ff 0%, #ffffff 100%);
}

.page-hero h1 {
    font-size: clamp(32px, 8vw, 52px);
    max-width: 860px;
}

.page-hero .lead {
    font-size: 17px;
    max-width: 820px;
}

.content-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
    align-items: start;
}

.article-panel,
.side-panel {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: var(--radius-xl);
    box-shadow: 0 12px 32px rgba(31, 41, 55, .05);
}

.article-panel {
    padding: 26px;
}

.article-panel h2 {
    margin-top: 26px;
    font-size: 24px;
}

.side-panel {
    padding: 22px;
}

.side-panel h3 {
    font-size: 18px;
}

.tip-box {
    margin: 22px 0;
    padding: 20px;
    background: #f5f9ff;
    border: 1px solid #d9e8ff;
    border-left: 4px solid var(--blue);
    border-radius: 20px;
}

.page-cta {
    margin-top: 28px;
    padding: 24px;
    border-radius: var(--radius-lg);
    background: #f5f7fb;
    border: 1px solid var(--line);
    text-align: center;
}

.download-steps {
    counter-reset: step;
    display: grid;
    gap: 16px;
    margin-top: 24px;
}

.download-step {
    counter-increment: step;
    padding: 20px;
    border-radius: 22px;
    background: #fff;
    border: 1px solid var(--line);
    display: grid;
    gap: 4px;
}

.download-step::before {
    content: counter(step);
    width: 34px;
    height: 34px;
    border-radius: 12px;
    background: var(--blue);
    color: #fff;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    margin-bottom: 6px;
}

.site-footer {
    background: #111827;
    color: #fff;
    padding: 42px 0 20px;
}

.footer-inner {
    width: min(1160px, calc(100% - 32px));
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr;
    gap: 28px;
    align-items: start;
}

.footer-brand {
    display: flex;
    gap: 14px;
    align-items: flex-start;
}

.footer-logo {
    width: 44px;
    height: 44px;
    border-radius: 14px;
    object-fit: cover;
}

.footer-brand p,
.footer-bottom {
    color: rgba(255,255,255,.66);
}

.footer-links {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.footer-links a {
    color: rgba(255,255,255,.82);
}

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

.footer-bottom {
    width: min(1160px, calc(100% - 32px));
    margin: 28px auto 0;
    padding-top: 18px;
    border-top: 1px solid rgba(255,255,255,.14);
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-size: 14px;
}

@media (min-width: 720px) {
    .summary-grid,
    .privacy-panel,
    .policy-grid,
    .tech-grid,
    .device-showcase,
    .process-steps,
    .risk-grid,
    .download-steps {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .article-panel {
        padding: 34px;
    }

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

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

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

    .hero-inner {
        grid-template-columns: 1.08fr .92fr;
        padding: 92px 0 118px;
    }

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

    .section {
        padding: 86px 0;
    }

    .module-grid,
    .split-section,
    .vpn-connection-section,
    .global-nodes-section,
    .high-speed-section,
    .multi-device-section {
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 54px;
    }

    .reverse-desktop .module-copy {
        order: 2;
    }

    .reverse-desktop .module-media {
        order: 1;
    }

    .privacy-panel {
        grid-template-columns: 1fr 1fr;
    }

    .no-log-policy-section .policy-grid,
    .encryption-protocol-section .tech-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

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

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

    .content-layout {
        grid-template-columns: minmax(0, 1fr) 320px;
    }

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

    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
    }
}

@media (max-width: 520px) {
    .header-inner {
        width: min(100% - 24px, 1160px);
    }

    .container,
    .narrow-container,
    .hero-inner,
    .footer-inner,
    .footer-bottom {
        width: min(100% - 24px, 1160px);
    }

    .section {
        padding: 52px 0;
    }

    .download-btn {
        width: 100%;
        min-height: 52px;
    }

    .hero-actions .download-btn {
        width: auto;
        min-width: 168px;
    }

    .float-card {
        position: static;
        margin: 8px 6px 0 0;
        display: inline-flex;
    }

    .hero-visual {
        display: block;
        min-height: auto;
    }

    .hero-device-card {
        margin-bottom: 12px;
    }
}