:root {
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --blue: #2980FE;
    --blue-dark: #1768E8;
    --text: #1F2937;
    --muted: #667085;
    --soft: #F5F7FB;
    --soft-blue: #F2F6FF;
    --border: #E6EAF2;
    --white: #FFFFFF;
    --shadow: 0 18px 50px rgba(31, 41, 55, .08);
    --radius: 28px;
}
* { 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: var(--text);
    background: #FFFFFF;
    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; }
.narrow { width: min(860px, calc(100% - 32px)); }
.gradient-bg { background: var(--gradient); color: #fff; }
.soft-bg { background: var(--soft); }
.section-pad { padding: 64px 0; }
.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: rgba(255,255,255,.92);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(230,234,242,.85);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; min-height: 68px; gap: 16px; }
.logo, .footer-logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: .02em; }
.logo img, .footer-logo img { width: 36px; height: 36px; object-fit: cover; border-radius: 12px; }
.site-nav { display: none; position: absolute; left: 16px; right: 16px; top: 68px; padding: 14px; background: #fff; border: 1px solid var(--border); border-radius: 20px; box-shadow: var(--shadow); }
.site-nav.is-open { display: grid; gap: 4px; }
.site-nav a { padding: 10px 12px; border-radius: 12px; color: #344054; font-size: 15px; }
.site-nav a:hover, .site-nav a[aria-current="page"] { background: var(--soft-blue); color: var(--blue); }
.nav-toggle { border: 1px solid var(--border); background: #fff; border-radius: 999px; padding: 8px 14px; color: #344054; font: inherit; }
.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 12px 24px;
    border-radius: 999px;
    background: var(--blue);
    color: #fff;
    font-weight: 700;
    box-shadow: 0 14px 28px rgba(41,128,254,.22);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}
.download-btn:hover { background: var(--blue-dark); transform: translateY(-1px); box-shadow: 0 18px 34px rgba(23,104,232,.26); }
.vpn-lab-hero { padding: 64px 0 44px; position: relative; overflow: hidden; }
.vpn-lab-hero:after { content: ""; position: absolute; inset: auto -20% -45% 30%; height: 260px; border-radius: 50%; background: rgba(255,255,255,.16); filter: blur(10px); }
.hero-grid { display: grid; gap: 36px; align-items: center; position: relative; z-index: 1; }
.eyebrow, .section-kicker, .badge, .mini-label { display: inline-flex; align-items: center; width: fit-content; border-radius: 999px; font-weight: 700; }
.eyebrow { padding: 6px 12px; background: rgba(255,255,255,.18); color: #fff; font-size: 13px; }
.hero-copy h1 { font-size: clamp(34px, 9vw, 64px); line-height: 1.08; margin: 18px 0; letter-spacing: -.04em; }
.hero-copy p { color: rgba(255,255,255,.88); font-size: 17px; margin: 0 0 24px; max-width: 650px; }
.hero-tags { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 18px; }
.hero-tags span { padding: 8px 12px; background: rgba(255,255,255,.16); border: 1px solid rgba(255,255,255,.24); border-radius: 999px; font-size: 13px; }
.hero-visual { position: relative; padding: 22px; border-radius: 34px; background: rgba(255,255,255,.16); border: 1px solid rgba(255,255,255,.25); box-shadow: 0 24px 70px rgba(22,34,80,.24); }
.hero-visual img { border-radius: 26px; margin: auto; }
.float-card { position: absolute; padding: 10px 13px; border-radius: 999px; background: #fff; color: #24304A; box-shadow: var(--shadow); font-size: 13px; font-weight: 700; }
.card-one { left: 10px; top: 22px; } .card-two { right: 12px; top: 32%; } .card-three { left: 16px; bottom: 22%; } .card-four { right: 20px; bottom: 18px; }
.section-heading { margin-bottom: 28px; }
.section-heading.compact { text-align: center; max-width: 760px; margin-inline: auto; }
.section-heading.align-left { text-align: left; }
.section-heading h2, .feature-copy h2, .protocol-panel h2, .device-layout h2 { font-size: clamp(26px, 5vw, 42px); line-height: 1.18; margin: 10px 0 12px; letter-spacing: -.03em; }
.section-heading p, .feature-copy p, .protocol-panel p, .device-layout p { color: var(--muted); margin: 0 0 18px; }
.section-kicker { padding: 6px 12px; background: #EAF2FF; color: var(--blue); font-size: 13px; }
.summary-grid, .three-panel-grid, .risk-grid, .mini-card-grid, .protocol-cards, .device-cards { display: grid; gap: 16px; }
.summary-grid article, .three-panel-grid article, .risk-grid article, .mini-card-grid article, .protocol-cards article, .device-cards article, .security-card, .article-panel, .side-panel, .notice-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: 0 12px 32px rgba(31,41,55,.05);
}
.summary-grid article { padding: 24px; }
.summary-grid h3, .three-panel-grid h3, .risk-grid h3, .mini-card-grid h3, .protocol-cards h3, .device-cards h3 { margin: 10px 0 8px; font-size: 20px; }
.summary-grid p, .three-panel-grid p, .risk-grid p, .mini-card-grid p, .protocol-cards p, .device-cards p { color: var(--muted); margin: 0 0 12px; }
.summary-grid a, .text-link, .process-steps a, .risk-grid a, .side-panel a { color: var(--blue); font-weight: 700; }
.mini-label { color: var(--blue); background: #EEF5FF; padding: 5px 10px; font-size: 12px; }
.feature-split, .privacy-panel-grid, .device-layout, .protocol-panel, .page-layout { display: grid; gap: 26px; align-items: center; }
.feature-media { padding: 18px; border-radius: 34px; background: linear-gradient(180deg, #F6F8FF 0%, #FFFFFF 100%); border: 1px solid var(--border); }
.feature-media img { border-radius: 24px; margin: auto; }
.clean-list { padding-left: 20px; color: #475467; }
.info-strip { margin: 18px 0; padding: 14px 16px; border-left: 4px solid var(--blue); border-radius: 14px; background: #F3F8FF; color: #344054; }
.large-card { padding: 18px; }
.large-card img { border-radius: 22px; margin-bottom: 16px; }
.tag-row { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; }
.tag-row span { background: #F2F6FF; color: var(--blue); border-radius: 999px; padding: 6px 10px; font-size: 12px; font-weight: 700; }
.three-panel-grid article, .protocol-cards article, .mini-card-grid article, .device-cards article { padding: 22px; }
.center-link { text-align: center; margin-top: 18px; }
.device-cards img { height: 150px; object-fit: contain; margin: auto; }
.protocol-panel { background: #fff; border: 1px solid var(--border); border-radius: 34px; padding: 24px; box-shadow: var(--shadow); }
.process-steps { display: grid; gap: 14px; }
.process-steps article { position: relative; padding: 22px; border-radius: 24px; background: #fff; border: 1px solid var(--border); }
.process-steps span { color: var(--blue); font-weight: 900; }
.process-steps h3 { margin: 8px 0; }
.process-steps p { margin: 0 0 8px; color: var(--muted); }
.risk-grid article { padding: 20px; border-left: 4px solid var(--blue); }
.risk-grid strong { color: #344054; margin-right: 6px; }
.faq-list { display: grid; gap: 12px; }
.faq-list details { background: #fff; border: 1px solid var(--border); border-radius: 20px; padding: 16px 18px; }
.faq-list summary { cursor: pointer; font-weight: 800; color: #1D2939; }
.faq-list p { color: var(--muted); margin: 10px 0 0; }
.cta-section { padding: 64px 0; }
.cta-inner { text-align: center; max-width: 760px; }
.cta-inner h2 { font-size: clamp(26px, 6vw, 44px); line-height: 1.18; margin: 14px 0 12px; }
.cta-inner p { color: rgba(255,255,255,.86); margin: 0 0 24px; }
.page-hero { padding: 58px 0; background: linear-gradient(180deg, #F4F7FF 0%, #FFFFFF 100%); border-bottom: 1px solid var(--border); }
.compact-hero h1 { font-size: clamp(32px, 8vw, 54px); line-height: 1.12; margin: 12px 0; letter-spacing: -.03em; }
.page-lead { color: var(--muted); font-size: 17px; margin: 0; }
.badge { background: #EAF2FF; color: var(--blue); padding: 7px 12px; font-size: 13px; }
.content-section { padding: 58px 0 72px; }
.article-panel { padding: 24px; }
.article-panel h2 { margin: 24px 0 10px; font-size: 24px; }
.article-panel h2:first-child { margin-top: 0; }
.article-panel p { color: #475467; margin: 0 0 14px; }
.article-panel .download-btn { margin-top: 20px; }
.side-panel { padding: 22px; align-self: start; }
.side-panel h3 { margin: 0 0 12px; }
.side-panel a { display: block; padding: 12px 0; border-bottom: 1px solid var(--border); }
.side-panel a:last-child { border-bottom: 0; }
.step-list { display: grid; gap: 12px; padding: 0; margin: 12px 0 22px; list-style: none; counter-reset: steps; }
.step-list li { padding: 16px; border-radius: 20px; background: #F8FAFF; border: 1px solid var(--border); }
.step-list span { display: block; color: var(--muted); margin-top: 4px; }
.notice-card { padding: 18px; margin: 16px 0; }
.soft-note { background: #F9FBFF; }
.single-cta { text-align: center; margin-top: 28px; }
.site-footer { background: #F7F8FB; padding: 42px 0 24px; color: #475467; border-top: 1px solid var(--border); }
.footer-grid { display: grid; gap: 26px; }
.footer-grid h3 { color: #1D2939; margin: 0 0 10px; font-size: 16px; }
.footer-grid a { display: block; color: #667085; margin: 8px 0; }
.footer-grid a:hover { color: var(--blue); }
.footer-bottom { margin-top: 28px; padding-top: 18px; border-top: 1px solid var(--border); display: flex; flex-direction: column; gap: 8px; font-size: 14px; }
@media (min-width: 720px) {
    .summary-grid, .three-panel-grid, .mini-card-grid { grid-template-columns: repeat(3, 1fr); }
    .risk-grid { grid-template-columns: repeat(2, 1fr); }
    .process-steps { grid-template-columns: repeat(2, 1fr); }
    .protocol-cards, .device-cards { grid-template-columns: repeat(3, 1fr); }
    .device-cards { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; }
    .footer-bottom { flex-direction: row; justify-content: space-between; }
}
@media (min-width: 940px) {
    .site-nav { position: static; display: flex; align-items: center; gap: 2px; padding: 0; background: transparent; border: 0; border-radius: 0; box-shadow: none; }
    .nav-toggle { display: none; }
    .hero-grid { grid-template-columns: 1.02fr .98fr; }
    .vpn-lab-hero { padding: 86px 0 68px; }
    .feature-split, .privacy-panel-grid, .device-layout, .protocol-panel, .page-layout { grid-template-columns: 1fr 1fr; }
    .feature-split.reverse .feature-media { order: 2; }
    .page-layout { grid-template-columns: minmax(0, 1fr) 320px; align-items: start; }
    .risk-grid { grid-template-columns: repeat(4, 1fr); }
    .process-steps { grid-template-columns: repeat(3, 1fr); }
    .section-pad { padding: 84px 0; }
    .article-panel { padding: 34px; }
    .content-section { padding: 72px 0 90px; }
}
@media (max-width: 420px) {
    .container, .narrow { width: min(100% - 24px, 1120px); }
    .download-btn { width: 100%; }
    .float-card { position: static; display: inline-flex; margin: 8px 6px 0 0; }
    .hero-visual { padding: 14px; }
    .section-pad { padding: 52px 0; }
    .article-panel, .side-panel { padding: 20px; }
}