:root {
    --primary: #2980FE;
    --primary-dark: #1768E8;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --text: #172033;
    --muted: #667085;
    --soft: #F4F7FB;
    --line: #E5EAF3;
    --white: #FFFFFF;
    --shadow: 0 20px 55px rgba(32, 60, 120, .12);
    --radius: 28px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
    color: var(--text);
    background: #F8FAFF;
    line-height: 1.75;
    overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
.container { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }
.section { padding: 56px 0; }
.section-title { max-width: 720px; margin: 0 auto 26px; text-align: center; }
.section-title h2 { margin: 0 0 10px; font-size: clamp(28px, 4vw, 44px); line-height: 1.2; }
.section-title p { margin: 0; color: var(--muted); }
.eyebrow, .category-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 12px;
    border-radius: 999px;
    background: rgba(41, 128, 254, .1);
    color: var(--primary);
    font-weight: 700;
    font-size: 14px;
}
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, .88);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid rgba(229, 234, 243, .78);
}
.header-inner {
    width: min(1180px, calc(100% - 28px));
    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; font-size: 20px; white-space: nowrap; }
.logo-img { width: 40px; height: 40px; object-fit: cover; border-radius: 12px; box-shadow: 0 8px 20px rgba(41, 128, 254, .18); }
.main-nav { display: none; width: 100%; padding: 12px 0 18px; flex-direction: column; gap: 8px; }
.main-nav.open { display: flex; }
.main-nav a { padding: 10px 12px; border-radius: 14px; color: #344054; font-weight: 650; font-size: 15px; }
.main-nav a:hover, .main-nav a.active { color: var(--primary); background: rgba(41, 128, 254, .08); }
.nav-toggle { display: inline-flex; flex-direction: column; gap: 5px; width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 14px; background: #fff; align-items: center; justify-content: center; }
.nav-toggle span { width: 18px; height: 2px; border-radius: 2px; background: #1f2937; }
.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 24px;
    border-radius: 999px;
    background: var(--primary);
    color: #fff;
    font-weight: 800;
    box-shadow: 0 15px 32px rgba(41, 128, 254, .28);
    transition: transform .2s ease, background .2s ease, box-shadow .2s ease;
}
.download-btn:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: 0 18px 36px rgba(23, 104, 232, .32); }
.vpn-saas-hero {
    position: relative;
    padding: 58px 0 44px;
    overflow: hidden;
    background: var(--gradient);
    color: #fff;
    isolation: isolate;
}
.vpn-saas-hero:after {
    content: "";
    position: absolute;
    left: -8%;
    right: -8%;
    bottom: -92px;
    height: 160px;
    background: #F8FAFF;
    transform: rotate(-4deg);
    z-index: -1;
}
.hero-grid { display: grid; gap: 34px; align-items: center; }
.hero-copy h1 { margin: 14px 0 16px; font-size: clamp(34px, 8vw, 64px); line-height: 1.08; letter-spacing: -.04em; }
.hero-copy p { margin: 0 0 24px; color: rgba(255,255,255,.86); font-size: 17px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.hero-tags span { padding: 7px 12px; border-radius: 999px; background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.24); font-weight: 700; font-size: 13px; }
.hero-visual { position: relative; padding: 12px; }
.product-card {
    position: relative;
    border-radius: 34px;
    background: rgba(255,255,255,.16);
    border: 1px solid rgba(255,255,255,.24);
    box-shadow: 0 30px 80px rgba(18, 31, 81, .28);
    padding: 22px;
    overflow: hidden;
}
.product-card img { margin: 0 auto; border-radius: 26px; }
.float-label { position: absolute; padding: 9px 12px; border-radius: 999px; background: rgba(255,255,255,.94); color: #1d2939; box-shadow: 0 14px 28px rgba(16,24,40,.12); font-size: 13px; font-weight: 800; }
.float-label.one { top: 8%; left: 0; }
.float-label.two { top: 22%; right: 0; }
.float-label.three { bottom: 25%; left: 2%; }
.float-label.four { bottom: 8%; right: 8%; }
.product-highlights { margin-top: -16px; position: relative; z-index: 2; }
.highlight-grid { display: grid; gap: 16px; }
.highlight-card, .feature-card, .risk-card, .faq-item, .info-card, .step-card {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 24px;
    box-shadow: 0 14px 35px rgba(16, 24, 40, .06);
}
.highlight-card { padding: 22px; }
.highlight-card .tag { color: var(--primary); font-weight: 900; font-size: 13px; }
.highlight-card h3, .feature-card h3, .risk-card h3, .info-card h3, .step-card h3 { margin: 8px 0 8px; line-height: 1.28; }
.highlight-card p, .feature-card p, .risk-card p, .info-card p, .step-card p { margin: 0 0 12px; color: var(--muted); }
.text-link { color: var(--primary); font-weight: 800; }
.split-section { display: grid; gap: 24px; align-items: center; }
.panel {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 26px;
    box-shadow: var(--shadow);
}
.panel h2 { margin: 0 0 12px; font-size: clamp(26px, 5vw, 42px); line-height: 1.18; }
.panel p { color: var(--muted); margin: 0 0 16px; }
.check-list { list-style: none; padding: 0; margin: 18px 0 18px; display: grid; gap: 10px; }
.check-list li { position: relative; padding-left: 26px; color: #344054; }
.check-list li:before { content: ""; position: absolute; left: 0; top: .6em; width: 10px; height: 10px; border-radius: 50%; background: var(--primary); box-shadow: 0 0 0 4px rgba(41,128,254,.12); }
.image-panel { background: linear-gradient(180deg, #fff, #EEF4FF); border: 1px solid var(--line); border-radius: 34px; padding: 22px; box-shadow: var(--shadow); }
.high-speed-section, .global-nodes-section, .multi-device-section { background: #F0F5FF; }
.speed-card { border-radius: 30px; padding: 24px; background: #fff; border: 1px solid var(--line); box-shadow: var(--shadow); }
.metric-row { display: grid; gap: 12px; margin-top: 20px; }
.metric { padding: 16px; border-radius: 20px; background: #F8FAFF; border: 1px solid var(--line); }
.metric strong { display: block; color: var(--primary); font-size: 22px; }
.global-layout { display: grid; gap: 22px; }
.node-list { display: grid; gap: 12px; }
.node-item { padding: 16px; border-radius: 20px; background: #fff; border: 1px solid var(--line); display: flex; justify-content: space-between; gap: 12px; }
.privacy-protection-section .privacy-panel { background: #fff; border-radius: 34px; border: 1px solid var(--line); padding: 26px; box-shadow: var(--shadow); }
.privacy-grid, .policy-grid, .protocol-grid, .risk-grid, .faq-grid, .article-grid, .guide-grid { display: grid; gap: 16px; }
.feature-card, .risk-card, .info-card { padding: 20px; }
.feature-card .mini, .risk-card .mini { color: var(--primary); font-weight: 900; font-size: 13px; }
.no-log-policy-section { background: #fff; }
.policy-strip { background: var(--gradient); color: #fff; border-radius: 34px; padding: 28px; box-shadow: var(--shadow); }
.policy-strip p { color: rgba(255,255,255,.86); }
.protocol-panel { background: #111827; color: #fff; border-radius: 34px; padding: 26px; box-shadow: var(--shadow); }
.protocol-panel p { color: rgba(255,255,255,.74); }
.protocol-grid .feature-card { background: rgba(255,255,255,.08); border-color: rgba(255,255,255,.16); color: #fff; }
.protocol-grid .feature-card p { color: rgba(255,255,255,.72); }
.process-steps { display: grid; gap: 16px; counter-reset: step; }
.step-card { padding: 20px; position: relative; overflow: hidden; }
.step-number { width: 38px; height: 38px; border-radius: 14px; background: rgba(41,128,254,.1); color: var(--primary); display: inline-flex; align-items: center; justify-content: center; font-weight: 900; }
.safety-panel { background: #fff; border: 1px solid var(--line); border-radius: 34px; padding: 24px; box-shadow: var(--shadow); }
.risk-card { border-left: 4px solid var(--primary); }
.faq-item { padding: 20px; }
.faq-item h3 { margin: 0 0 8px; font-size: 18px; }
.faq-item p { margin: 0; color: var(--muted); }
.cta-section { padding: 58px 0; }
.cta-card { text-align: center; color: #fff; background: var(--gradient); border-radius: 36px; padding: 38px 24px; box-shadow: var(--shadow); overflow: hidden; position: relative; }
.cta-card h2 { margin: 0 0 10px; font-size: clamp(28px, 5vw, 46px); }
.cta-card p { margin: 0 auto 22px; max-width: 680px; color: rgba(255,255,255,.86); }
.page-hero { padding: 48px 0 34px; background: radial-gradient(circle at 20% 20%, rgba(41,128,254,.16), transparent 28%), #F8FAFF; }
.page-hero-inner { background: #fff; border: 1px solid var(--line); border-radius: 34px; padding: 28px; box-shadow: var(--shadow); }
.page-hero h1 { margin: 14px 0 12px; font-size: clamp(30px, 6vw, 54px); line-height: 1.12; }
.page-hero p { margin: 0; color: var(--muted); max-width: 820px; }
.article-layout { display: grid; gap: 20px; align-items: start; }
.article-main { display: grid; gap: 18px; }
.article-card { background: #fff; border: 1px solid var(--line); border-radius: 28px; padding: 24px; box-shadow: 0 14px 35px rgba(16,24,40,.05); }
.article-card h2 { margin: 0 0 10px; }
.article-card p { color: var(--muted); margin: 0 0 12px; }
.sidebar-card { background: #fff; border: 1px solid var(--line); border-radius: 28px; padding: 20px; position: sticky; top: 92px; box-shadow: 0 14px 35px rgba(16,24,40,.05); }
.sidebar-card a { display: block; padding: 10px 0; color: var(--primary); font-weight: 800; border-bottom: 1px solid var(--line); }
.sidebar-card a:last-child { border-bottom: 0; }
.notice-box { padding: 18px; border-radius: 22px; background: #F0F6FF; border: 1px solid #D8E7FF; color: #344054; }
.steps-list { margin: 0; padding-left: 20px; color: #344054; }
.steps-list li { margin: 8px 0; }
.download-page-card { text-align: center; max-width: 860px; margin: 0 auto; }
.download-page-card .download-btn { margin-top: 10px; }
.site-footer { background: #101828; color: rgba(255,255,255,.72); padding: 44px 0 20px; }
.footer-grid { display: grid; gap: 24px; }
.footer-brand { color: #fff; font-size: 24px; font-weight: 900; margin-bottom: 10px; }
.site-footer h3 { color: #fff; margin: 0 0 10px; }
.site-footer a { display: block; margin: 7px 0; color: rgba(255,255,255,.72); }
.site-footer a:hover { color: #fff; }
.footer-bottom { width: min(1120px, calc(100% - 32px)); margin: 28px auto 0; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.12); text-align: center; font-size: 14px; }
@media (min-width: 640px) {
    .highlight-grid, .privacy-grid, .policy-grid, .risk-grid, .faq-grid, .guide-grid, .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .metric-row { grid-template-columns: repeat(3, 1fr); }
    .process-steps { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 920px) {
    .header-inner { min-height: 78px; }
    .nav-toggle { display: none; }
    .main-nav { display: flex; flex-direction: row; align-items: center; justify-content: flex-end; gap: 4px; padding: 0; width: auto; }
    .main-nav a { font-size: 14px; padding: 9px 10px; }
    .hero-grid, .split-section, .global-layout { grid-template-columns: 1.05fr .95fr; }
    .vpn-saas-hero { padding: 86px 0 82px; }
    .highlight-grid { grid-template-columns: repeat(4, 1fr); }
    .privacy-grid, .policy-grid, .protocol-grid { grid-template-columns: repeat(3, 1fr); }
    .risk-grid { grid-template-columns: repeat(4, 1fr); }
    .faq-grid { grid-template-columns: repeat(2, 1fr); }
    .article-layout { grid-template-columns: minmax(0, 1fr) 300px; }
    .article-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; }
    .process-steps { grid-template-columns: repeat(3, 1fr); }
    .section { padding: 78px 0; }
}
@media (min-width: 1120px) {
    .main-nav a { padding: 10px 12px; }
}
@media (max-width: 420px) {
    .container { width: min(100% - 24px, 1120px); }
    .panel, .page-hero-inner, .privacy-protection-section .privacy-panel, .safety-panel { padding: 20px; border-radius: 24px; }
    .float-label { position: static; display: inline-flex; margin: 8px 6px 0 0; }
    .hero-visual { padding: 0; }
    .download-btn { width: 100%; }
}