/* body */
:root {
    --blue: #2980FE;
    --blue-dark: #1768E8;
    --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
    --text: #1f2937;
    --muted: #667085;
    --light: #f5f7fb;
    --line: #e6eaf2;
    --white: #ffffff;
    --deep: #111827;
    --shadow: 0 18px 45px rgba(32, 55, 120, 0.10);
    --radius: 24px;
}
* { 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: #f8fafc;
    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-container { width: min(900px, calc(100% - 32px)); margin: 0 auto; }
.section { padding: 64px 0; }
.section-muted { background: #f2f6ff; }
.section-title { margin-bottom: 26px; }
.section-title .eyebrow, .eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--blue);
    background: rgba(41,128,254,0.10);
    border: 1px solid rgba(41,128,254,0.18);
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
}
.section-title h2, .content-card h2 { font-size: clamp(26px, 4vw, 42px); line-height: 1.2; margin: 14px 0 12px; color: var(--deep); }
.section-title p { color: var(--muted); max-width: 760px; margin: 0; }

/* header */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255,255,255,0.94);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid var(--line);
}
.header-inner {
    width: min(1180px, calc(100% - 28px));
    margin: 0 auto;
    min-height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}
/* logo */
.logo, .footer-logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; color: var(--deep); }
.logo img, .footer-logo img { width: 38px; height: 38px; border-radius: 12px; object-fit: cover; }
/* responsive nav */
.nav-toggle { display: none; }
.nav-toggle-label { width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 14px; display: flex; flex-direction: column; justify-content: center; gap: 5px; padding: 0 10px; cursor: pointer; background: var(--white); }
.nav-toggle-label span { height: 2px; background: var(--deep); border-radius: 8px; }
/* mobile nav */
.site-nav {
    position: absolute;
    left: 14px;
    right: 14px;
    top: 70px;
    display: none;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    background: var(--white);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
    border-radius: 18px;
    padding: 12px;
}
.nav-toggle:checked ~ .site-nav { display: grid; }
.site-nav a { padding: 10px 12px; border-radius: 12px; color: #344054; font-size: 14px; font-weight: 700; }
.site-nav a:hover, .site-nav a.active { background: rgba(41,128,254,0.10); color: var(--blue); }

/* unified download button */
.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: 800;
    letter-spacing: .02em;
    box-shadow: 0 12px 28px 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 36px rgba(23,104,232,.26); }
.text-link { color: var(--blue); font-weight: 800; }
.text-link:hover { color: var(--blue-dark); }

/* gradient background */
.gradient-bg { background: var(--gradient); color: #fff; }

/* vpn network hero */
.vpn-network-hero {
    position: relative;
    overflow: hidden;
    background: var(--gradient);
    color: #fff;
    padding: 54px 0 34px;
}
.vpn-network-hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 18% 20%, rgba(255,255,255,.28), transparent 24%),
        radial-gradient(circle at 82% 38%, rgba(255,255,255,.20), transparent 24%),
        linear-gradient(135deg, rgba(255,255,255,.16) 1px, transparent 1px),
        linear-gradient(45deg, rgba(255,255,255,.10) 1px, transparent 1px);
    background-size: auto, auto, 46px 46px, 66px 66px;
    opacity: .75;
}
.hero-inner { position: relative; display: grid; gap: 34px; align-items: center; }
.hero-copy h1 { font-size: clamp(36px, 9vw, 68px); line-height: 1.05; margin: 0 0 18px; letter-spacing: -0.04em; }
.hero-copy p { font-size: 17px; color: rgba(255,255,255,.88); margin: 0 0 24px; max-width: 640px; }
.hero-tags, .floating-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.hero-tags span, .floating-tags span { border: 1px solid rgba(255,255,255,.30); background: rgba(255,255,255,.16); color: #fff; padding: 7px 12px; border-radius: 999px; font-size: 13px; font-weight: 700; }
.hero-visual { position: relative; min-height: 310px; display: grid; place-items: center; }
.hero-device { width: min(420px, 88%); background: rgba(255,255,255,.18); border: 1px solid rgba(255,255,255,.30); border-radius: 32px; padding: 18px; box-shadow: 0 30px 90px rgba(20, 30, 80, .28); }
.hero-device img { border-radius: 24px; width: 100%; }
.status-card { position: absolute; background: rgba(255,255,255,.92); color: var(--deep); border: 1px solid rgba(255,255,255,.70); box-shadow: 0 18px 42px rgba(19,24,60,.20); border-radius: 18px; padding: 10px 14px; font-weight: 800; font-size: 13px; }
.status-card small { display: block; color: var(--blue); font-weight: 800; }
.status-one { top: 24px; left: 6px; }
.status-two { top: 46%; right: 0; }
.status-three { bottom: 14px; left: 20px; }
.status-four { bottom: 72px; right: 36px; }

/* node overview */
.node-overview { margin-top: -18px; position: relative; z-index: 2; }
.node-grid { display: grid; gap: 16px; }
/* node card */
.node-card {
    background: var(--white);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 22px;
    box-shadow: var(--shadow);
}
.node-card .tag { display: inline-block; color: var(--blue); background: rgba(41,128,254,.10); border-radius: 999px; padding: 4px 10px; font-size: 12px; font-weight: 800; }
.node-card h3 { margin: 13px 0 8px; color: var(--deep); }
.node-card p { color: var(--muted); margin: 0 0 12px; }

/* vpn connection section */
.vpn-connection-section .feature-panel, .split-panel { display: grid; gap: 28px; align-items: center; }
.image-panel { background: var(--white); border: 1px solid var(--line); border-radius: 32px; padding: 18px; box-shadow: var(--shadow); }
.image-panel img { border-radius: 24px; margin: 0 auto; }
.content-card { background: var(--white); border: 1px solid var(--line); border-radius: 32px; padding: 28px; box-shadow: var(--shadow); }
.feature-list, .clean-list { list-style: none; padding: 0; margin: 18px 0 0; display: grid; gap: 12px; }
.feature-list li, .clean-list li { padding: 14px 16px; border-radius: 18px; background: #f7f9fe; border: 1px solid var(--line); color: #344054; }
.feature-list li strong { color: var(--deep); }

/* global nodes section */
.global-nodes-section { position: relative; overflow: hidden; }
.map-panel { background: linear-gradient(180deg, #ffffff 0%, #eef4ff 100%); border: 1px solid var(--line); border-radius: 32px; padding: 22px; box-shadow: var(--shadow); position: relative; overflow: hidden; }
.map-panel::before { content: ""; position: absolute; inset: 18px; border-radius: 28px; background-image: radial-gradient(circle, rgba(41,128,254,.32) 2px, transparent 3px), linear-gradient(90deg, rgba(41,128,254,.10) 1px, transparent 1px), linear-gradient(0deg, rgba(41,128,254,.08) 1px, transparent 1px); background-size: 72px 72px, 52px 52px, 52px 52px; }
.map-panel img { position: relative; z-index: 1; border-radius: 22px; margin: 0 auto; }
.node-note-grid { display: grid; gap: 14px; margin-top: 18px; }
.node-note { background: rgba(255,255,255,.92); border: 1px solid var(--line); border-radius: 18px; padding: 16px; }
.node-note strong { display: block; color: var(--deep); margin-bottom: 4px; }
.node-note span { color: var(--muted); }

/* high speed section */
.high-speed-section { background: #f2f6ff; }
.speed-lines { display: grid; gap: 14px; }
.speed-line { background: var(--white); border: 1px solid var(--line); border-radius: 20px; padding: 16px; display: grid; gap: 10px; }
.speed-track { height: 9px; border-radius: 999px; background: #e7eefb; overflow: hidden; }
.speed-track span { display: block; height: 100%; border-radius: 999px; background: var(--blue); }

/* privacy protection section */
.privacy-protection-section .privacy-panel { display: grid; gap: 18px; }
.privacy-badge-grid { display: grid; gap: 12px; }
.privacy-badge { background: #f7f9fe; border: 1px solid var(--line); border-radius: 18px; padding: 16px; }
.privacy-badge strong { display: block; color: var(--deep); margin-bottom: 4px; }
.privacy-badge span { color: var(--muted); }

/* no log policy section */
.no-log-policy-section .policy-grid { display: grid; gap: 16px; }
.policy-card { background: var(--white); border: 1px solid var(--line); border-radius: 24px; padding: 22px; box-shadow: var(--shadow); }
.policy-card h3 { margin: 0 0 10px; color: var(--deep); }
.policy-card p { margin: 0; color: var(--muted); }

/* multi device section */
.multi-device-section .device-grid { display: grid; gap: 16px; }
.device-card { background: #f7f9fe; border: 1px solid var(--line); border-radius: 20px; padding: 18px; }
.device-card h3 { margin: 0 0 6px; color: var(--deep); }
.device-card p { margin: 0; color: var(--muted); }

/* encryption protocol section */
.encryption-protocol-section .protocol-panel { background: #101828; color: #fff; border-radius: 32px; padding: 28px; display: grid; gap: 18px; position: relative; overflow: hidden; }
.protocol-panel::after { content: ""; position: absolute; width: 260px; height: 260px; border-radius: 50%; right: -120px; top: -120px; background: rgba(41,128,254,.28); }
.protocol-panel p { color: rgba(255,255,255,.78); }
.protocol-grid { display: grid; gap: 14px; position: relative; z-index: 1; }
.protocol-card { background: rgba(255,255,255,.09); border: 1px solid rgba(255,255,255,.14); border-radius: 18px; padding: 16px; }
.protocol-card strong { display: block; }
.protocol-card span { color: rgba(255,255,255,.72); }

/* content container */
.page-hero { background: linear-gradient(180deg, #eef4ff 0%, #ffffff 100%); padding: 58px 0 34px; border-bottom: 1px solid var(--line); }
.page-hero h1 { font-size: clamp(34px, 7vw, 56px); line-height: 1.12; margin: 12px 0; color: var(--deep); letter-spacing: -0.03em; }
.page-hero p { max-width: 760px; color: var(--muted); margin: 0; }
.content-layout { display: grid; gap: 22px; align-items: start; }
.article-card { background: var(--white); border: 1px solid var(--line); border-radius: 30px; padding: 26px; box-shadow: var(--shadow); }
.article-card h2 { color: var(--deep); margin-top: 0; }
.article-card p { color: #485467; }
.sidebar-card { background: #f7f9fe; border: 1px solid var(--line); border-radius: 24px; padding: 20px; }
.sidebar-card h3 { margin-top: 0; color: var(--deep); }
.sidebar-card a { display: block; color: var(--blue); font-weight: 800; margin: 8px 0; }
.info-grid { display: grid; gap: 14px; margin: 20px 0; }
.info-card { background: #f7f9fe; border: 1px solid var(--line); border-radius: 18px; padding: 16px; }
.info-card strong { display: block; color: var(--deep); margin-bottom: 5px; }
.info-card span { color: var(--muted); }

/* safety panel */
.safety-panel { background: #ffffff; border: 1px solid var(--line); border-radius: 28px; padding: 24px; box-shadow: var(--shadow); }
.safety-panel h2 { margin-top: 0; color: var(--deep); }

/* process steps */
.process-steps { display: grid; gap: 16px; }
.step-card { background: var(--white); border: 1px solid var(--line); border-radius: 22px; padding: 20px; box-shadow: 0 12px 30px rgba(32,55,120,.07); }
.step-num { width: 38px; height: 38px; border-radius: 14px; display: inline-grid; place-items: center; background: var(--blue); color: #fff; font-weight: 900; margin-bottom: 10px; }
.step-card h3 { margin: 0 0 6px; color: var(--deep); }
.step-card p { margin: 0 0 10px; color: var(--muted); }

/* risk grid */
.risk-grid { display: grid; gap: 16px; }
.risk-card { background: var(--white); border: 1px solid var(--line); border-left: 4px solid var(--blue); border-radius: 20px; padding: 18px; }
.risk-card h3 { margin: 0 0 6px; color: var(--deep); }
.risk-card p { margin: 0 0 8px; color: var(--muted); }
.risk-card strong { color: var(--blue); }

/* FAQ item */
.faq-list { display: grid; gap: 14px; }
.faq-item { background: var(--white); border: 1px solid var(--line); border-radius: 20px; padding: 18px 20px; }
.faq-item h3 { margin: 0 0 8px; color: var(--deep); }
.faq-item p { margin: 0; color: var(--muted); }

/* cta */
.cta-section { padding: 58px 0; background: var(--gradient); color: #fff; text-align: center; position: relative; overflow: hidden; }
.cta-section::before { content: ""; position: absolute; inset: 0; background: radial-gradient(circle at 20% 20%, rgba(255,255,255,.22), transparent 26%), radial-gradient(circle at 80% 50%, rgba(255,255,255,.14), transparent 30%); }
.cta-section .container { position: relative; }
.cta-section h2 { font-size: clamp(28px, 5vw, 44px); margin: 0 0 12px; }
.cta-section p { color: rgba(255,255,255,.84); max-width: 720px; margin: 0 auto 22px; }

/* footer */
.site-footer { background: #111827; color: rgba(255,255,255,.72); padding-top: 46px; }
.footer-grid { display: grid; gap: 24px; }
.footer-logo { color: #fff; margin-bottom: 12px; }
.site-footer h3 { color: #fff; margin: 0 0 12px; }
.site-footer a { display: block; color: rgba(255,255,255,.70); margin: 7px 0; }
.site-footer a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.12); margin-top: 32px; padding: 18px; text-align: center; color: rgba(255,255,255,.58); }

@media (min-width: 680px) {
    .node-grid, .policy-grid, .device-grid, .risk-grid, .info-grid, .privacy-badge-grid { grid-template-columns: repeat(2, 1fr); }
    .process-steps { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1.5fr 1fr 1fr 1fr; }
}
/* desktop nav */
@media (min-width: 960px) {
    .nav-toggle-label { display: none; }
    .site-nav { position: static; display: flex; align-items: center; gap: 4px; background: transparent; border: 0; box-shadow: none; padding: 0; }
    .site-nav a { font-size: 14px; padding: 9px 10px; }
    .vpn-network-hero { padding: 86px 0 56px; }
    .hero-inner { grid-template-columns: 1.02fr .98fr; }
    .hero-copy p { font-size: 18px; }
    .node-grid { grid-template-columns: repeat(4, 1fr); }
    .vpn-connection-section .feature-panel, .split-panel { grid-template-columns: 1fr 1fr; }
    .global-nodes-section .split-panel { grid-template-columns: .9fr 1.1fr; }
    .policy-grid, .risk-grid { grid-template-columns: repeat(3, 1fr); }
    .process-steps { grid-template-columns: repeat(3, 1fr); }
    .content-layout { grid-template-columns: minmax(0, 1fr) 300px; }
    .article-card { padding: 36px; }
}
@media (max-width: 420px) {
    .container, .narrow-container { width: min(100% - 24px, 1120px); }
    .hero-copy h1 { font-size: 34px; }
    .section { padding: 48px 0; }
    .content-card, .article-card { padding: 22px; border-radius: 24px; }
    .download-btn { width: 100%; }
    .site-nav { grid-template-columns: 1fr; }
}