:root {
  --primary: #2980FE;
  --primary-dark: #1768E8;
  --gradient: linear-gradient(90deg, #3558F2 0%, #7B4EF1 50%, #B84DDA 100%);
  --text: #1f2937;
  --muted: #5f6b7a;
  --soft: #f5f7fb;
  --line: #e5e9f2;
  --white: #ffffff;
  --shadow: 0 16px 45px rgba(41, 92, 170, .10);
  --radius: 24px;
}
* { 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: #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; }
.gradient-bg { background: var(--gradient); color: #fff; }
.soft-bg { background: var(--soft); }
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255,255,255,.94);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(229,233,242,.85);
}
.nav-wrap { display: flex; align-items: center; justify-content: space-between; min-height: 68px; gap: 18px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 800; color: #172033; letter-spacing: .02em; }
.logo img { width: 38px; height: 38px; object-fit: cover; border-radius: 12px; }
.nav-toggle { display: none; }
.nav-toggle-label { width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 14px; display: grid; place-content: center; gap: 5px; cursor: pointer; }
.nav-toggle-label span { width: 18px; height: 2px; background: #273142; border-radius: 3px; display: block; }
.site-nav { display: none; position: absolute; top: 68px; left: 16px; right: 16px; background: #fff; border: 1px solid var(--line); border-radius: 20px; padding: 12px; box-shadow: var(--shadow); }
.site-nav a { display: block; padding: 11px 14px; border-radius: 12px; color: #3c4656; font-size: 15px; }
.site-nav a:hover, .site-nav a.active { color: var(--primary); background: #edf5ff; }
.nav-toggle:checked ~ .site-nav { display: block; }
.download-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 12px 26px;
  border-radius: 999px;
  background: var(--primary);
  color: #fff;
  font-weight: 800;
  box-shadow: 0 12px 28px rgba(41,128,254,.24);
  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 34px rgba(23,104,232,.28); }
.vpn-network-hero { position: relative; padding: 72px 0 96px; overflow: hidden; }
.hero-network-lines { position: absolute; inset: 0; opacity: .36; background-image: radial-gradient(circle at 20% 30%, rgba(255,255,255,.65) 0 2px, transparent 3px), radial-gradient(circle at 72% 38%, rgba(255,255,255,.5) 0 2px, transparent 3px), linear-gradient(120deg, transparent 0 18%, rgba(255,255,255,.16) 18.4%, transparent 19%), linear-gradient(30deg, transparent 0 58%, rgba(255,255,255,.12) 58.4%, transparent 59%); }
.hero-grid { position: relative; display: grid; gap: 34px; align-items: center; }
.hero-copy h1 { font-size: clamp(34px, 9vw, 64px); line-height: 1.08; margin: 14px 0 18px; letter-spacing: -.04em; }
.hero-copy p { font-size: 17px; color: rgba(255,255,255,.88); max-width: 640px; margin-bottom: 24px; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; color: var(--primary); font-weight: 800; font-size: 14px; letter-spacing: .08em; }
.eyebrow.light { color: rgba(255,255,255,.88); }
.hero-tags, .badge-row, .side-pills { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.hero-tags span, .badge-row span, .side-pills span, .mini-grid span, .speed-lines span { padding: 8px 12px; border-radius: 999px; background: rgba(255,255,255,.16); color: #fff; border: 1px solid rgba(255,255,255,.25); font-size: 13px; }
.hero-visual { position: relative; min-height: 340px; display: grid; place-items: center; }
.hero-visual img { width: min(420px, 90%); border-radius: 30px; filter: drop-shadow(0 24px 42px rgba(13, 20, 76, .28)); }
.float-card { position: absolute; background: rgba(255,255,255,.92); color: #263449; padding: 10px 14px; border-radius: 16px; font-weight: 800; box-shadow: 0 18px 45px rgba(17,30,79,.18); border: 1px solid rgba(255,255,255,.55); }
.card-a { left: 2%; top: 16%; } .card-b { right: 5%; top: 22%; } .card-c { left: 8%; bottom: 18%; } .card-d { right: 2%; bottom: 20%; }
.section-offset { margin-top: -48px; position: relative; z-index: 2; }
.section-heading { max-width: 720px; margin-bottom: 28px; }
.section-heading.center { text-align: center; margin-left: auto; margin-right: auto; }
.section-heading h2, .content-panel h2, .map-copy h2, .privacy-panel h2, .protocol-grid h2, .cta-inner h2 { margin: 8px 0 12px; font-size: clamp(26px, 5vw, 42px); line-height: 1.2; letter-spacing: -.03em; }
.section-heading p, .content-panel p, .map-copy p, .privacy-panel p, .protocol-grid p, .article-main p, .page-summary { color: var(--muted); }
.node-overview { padding-bottom: 42px; }
.overview-grid { display: grid; gap: 16px; }
.node-card, .three-cards article, .risk-grid article, .info-cards article, .process-steps article, .article-side, .faq-item { background: #fff; border: 1px solid var(--line); border-radius: 22px; padding: 22px; box-shadow: 0 10px 28px rgba(44,68,105,.06); }
.node-card span { display: inline-block; color: var(--primary); font-weight: 800; font-size: 13px; margin-bottom: 10px; }
.node-card h3, .three-cards h3, .risk-grid h3, .info-cards h3, .process-steps h3 { margin: 0 0 8px; font-size: 19px; }
.node-card p, .three-cards p, .risk-grid p, .info-cards p, .process-steps p { color: var(--muted); margin: 0 0 12px; }
.node-card a, .three-cards a, .risk-grid a, .process-steps a, .text-link, .side-links a { color: var(--primary); font-weight: 800; }
.feature-section, .article-section, .process-section, .faq-summary { padding: 72px 0; }
.split-grid, .map-card, .privacy-panel, .protocol-grid, .article-grid, .about-grid { display: grid; gap: 28px; align-items: center; }
.image-panel, .device-stack, .security-board, .protocol-card, .side-visual { background: #fff; border: 1px solid var(--line); border-radius: 30px; padding: 18px; box-shadow: var(--shadow); overflow: hidden; }
.image-panel img, .device-stack img, .security-board img, .protocol-card img, .side-visual img { border-radius: 22px; width: 100%; }
.check-list { list-style: none; padding: 0; margin: 18px 0; display: grid; gap: 10px; }
.check-list li { padding-left: 28px; position: relative; color: #334155; }
.check-list li::before { content: ""; width: 10px; height: 10px; border-radius: 50%; background: var(--primary); position: absolute; left: 0; top: .72em; box-shadow: 0 0 0 5px #e7f1ff; }
.map-card { position: relative; overflow: hidden; background: #fff; border: 1px solid var(--line); border-radius: 32px; padding: 22px; box-shadow: var(--shadow); }
.map-card::before { content: ""; position: absolute; inset: 0; background-image: radial-gradient(circle at 18% 40%, rgba(41,128,254,.18) 0 3px, transparent 4px), radial-gradient(circle at 70% 28%, rgba(123,78,241,.16) 0 3px, transparent 4px), radial-gradient(circle at 88% 68%, rgba(184,77,218,.14) 0 3px, transparent 4px); pointer-events: none; }
.map-copy, .map-visual { position: relative; }
.mini-grid, .speed-lines { display: flex; gap: 10px; flex-wrap: wrap; margin: 20px 0; }
.mini-grid span, .speed-lines span { background: #edf5ff; color: #2f5fa5; border-color: #cfe3ff; }
.speed-panel { background: #fff; border: 1px solid var(--line); border-radius: 30px; padding: 26px; box-shadow: var(--shadow); }
.security-board .badge-row span { background: #f0f6ff; color: #2d5f9f; border-color: #d9e8ff; }
.three-cards, .risk-grid, .info-cards, .process-steps { display: grid; gap: 16px; }
.protocol-card ul { margin: 16px 0 0; padding: 0; list-style: none; display: grid; gap: 10px; }
.protocol-card li { padding: 12px 14px; border-radius: 14px; background: #f3f7fe; color: #344054; font-weight: 700; }
.process-steps article b { display: inline-grid; place-items: center; width: 42px; height: 42px; border-radius: 14px; background: var(--gradient); color: #fff; margin-bottom: 14px; }
.risk-grid article { border-left: 4px solid var(--primary); }
.risk-grid strong { display: block; color: #29384d; margin: 10px 0; }
.faq-list { display: grid; gap: 14px; max-width: 860px; margin: 0 auto; }
.faq-item summary { cursor: pointer; font-weight: 800; color: #172033; }
.faq-item p { color: var(--muted); margin-bottom: 0; }
.cta-section { padding: 78px 0; text-align: center; }
.cta-inner p { color: rgba(255,255,255,.86); max-width: 640px; margin: 0 auto 24px; }
.cta-section .download-btn { background: var(--primary); }
.page-hero { padding: 64px 0; background: linear-gradient(180deg, #f7f9ff 0%, #ffffff 100%); }
.slim-hero { border-bottom: 1px solid var(--line); }
.about-hero, .download-hero { background: linear-gradient(135deg, #eef5ff 0%, #f8f3ff 100%); }
.category-badge { display: inline-flex; padding: 8px 12px; border-radius: 999px; color: var(--primary); background: #eaf3ff; border: 1px solid #d8e8ff; font-weight: 800; }
.page-hero h1 { font-size: clamp(32px, 7vw, 54px); line-height: 1.12; letter-spacing: -.035em; margin: 16px 0; }
.page-summary { font-size: 17px; margin-bottom: 24px; max-width: 720px; }
.article-layout { display: grid; gap: 24px; align-items: start; }
.article-main { min-width: 0; }
.article-main h2 { font-size: 26px; margin: 26px 0 8px; letter-spacing: -.02em; }
.article-main > p { font-size: 16px; margin: 0 0 18px; }
.article-side { position: sticky; top: 92px; }
.article-side h2 { margin-top: 0; font-size: 20px; }
.side-links { display: grid; gap: 10px; }
.side-links a { padding: 12px 14px; border-radius: 14px; background: #f0f6ff; }
.strong-side { background: var(--gradient); color: #fff; }
.strong-side p { color: rgba(255,255,255,.88); }
.ordered-steps { padding-left: 20px; color: var(--muted); }
.ordered-steps li { margin: 12px 0; }
.two-col { grid-template-columns: 1fr; }
.site-footer { background: #111827; color: #d1d5db; padding-top: 54px; }
.footer-grid { display: grid; gap: 28px; }
.footer-brand { display: flex; align-items: center; gap: 10px; color: #fff; font-size: 18px; }
.footer-brand img { width: 40px; height: 40px; border-radius: 12px; object-fit: cover; }
.site-footer h3 { color: #fff; margin: 0 0 12px; }
.site-footer a { display: block; color: #d1d5db; margin: 8px 0; }
.site-footer a:hover { color: #fff; }
.footer-note { color: #a8b0bd; }
.footer-bottom { text-align: center; border-top: 1px solid rgba(255,255,255,.08); margin-top: 32px; padding: 18px; color: #9ca3af; }
@media (min-width: 640px) {
  .container { width: min(1120px, calc(100% - 48px)); }
  .overview-grid, .three-cards, .risk-grid, .info-cards, .process-steps { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .two-col { grid-template-columns: repeat(2, minmax(0,1fr)); }
}
@media (min-width: 900px) {
  .nav-toggle-label { display: none; }
  .site-nav { display: flex; position: static; background: transparent; border: 0; box-shadow: none; padding: 0; gap: 4px; align-items: center; }
  .site-nav a { padding: 9px 12px; font-size: 14px; white-space: nowrap; }
  .hero-grid, .split-grid, .map-card, .privacy-panel, .protocol-grid, .article-grid { grid-template-columns: 1.02fr .98fr; }
  .reverse { grid-template-columns: .95fr 1.05fr; }
  .overview-grid { grid-template-columns: repeat(4, minmax(0,1fr)); }
  .three-cards { grid-template-columns: repeat(3, minmax(0,1fr)); }
  .risk-grid { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .process-steps { grid-template-columns: repeat(3, minmax(0,1fr)); }
  .article-layout, .about-grid { grid-template-columns: minmax(0,1fr) 300px; }
  .article-layout.alt-layout { grid-template-columns: minmax(0,1fr) 320px; }
  .vpn-network-hero { padding: 94px 0 118px; }
  .map-card { padding: 44px; }
  .content-panel { padding: 10px 20px; }
  .footer-grid { grid-template-columns: 1.4fr .8fr .8fr .8fr; }
}
@media (min-width: 1120px) {
  .risk-grid { grid-template-columns: repeat(4, minmax(0,1fr)); }
}
@media (max-width: 420px) {
  .container { width: min(100% - 24px, 1120px); }
  .download-btn { width: 100%; }
  .float-card { font-size: 12px; padding: 8px 10px; }
  .card-a { left: 0; } .card-b { right: 0; } .card-c { left: 0; } .card-d { right: 0; }
  .feature-section, .article-section, .process-section, .faq-summary { padding: 52px 0; }
  .page-hero { padding: 46px 0; }
}