:root {
  --primary: #3b82f6;
  --primary-dark: #2563eb;
  --primary-soft: #eff6ff;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;
  --surface: #f7f9fc;
  --white: #fff;
  --success: #16a34a;
  --error: #ef4444;
  --shadow: 0 18px 50px rgba(15, 23, 42, 0.08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--text);
  background: var(--white);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

body.menu-open { overflow: hidden; }

a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
img, svg { display: block; max-width: 100%; }

.container { width: min(1120px, calc(100% - 48px)); margin: 0 auto; }
.section { padding: 96px 0; }
.section-soft { background: var(--surface); }

.section-heading { max-width: 620px; margin: 0 auto 48px; text-align: center; }
.section-kicker { margin: 0 0 10px; color: var(--primary-dark); font-size: 14px; font-weight: 700; letter-spacing: .12em; }
.section-heading h2 { margin: 0 0 12px; font-size: clamp(30px, 4vw, 42px); line-height: 1.2; letter-spacing: -.03em; }
.section-heading p { margin: 0; color: var(--muted); font-size: 17px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid rgba(229, 231, 235, .8);
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(12px);
}

.navbar { min-height: 72px; display: flex; align-items: center; justify-content: space-between; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-size: 20px; font-weight: 800; letter-spacing: -.02em; }
.brand img { width: 36px; height: 36px; }
.nav-links { display: flex; align-items: center; gap: 30px; }
.nav-links a { color: #374151; font-size: 15px; font-weight: 600; transition: color .2s; }
.nav-links a:hover { color: var(--primary); }
.nav-links .nav-primary { padding: 9px 18px; color: var(--white); background: var(--primary); border-radius: 8px; }
.nav-links .nav-primary:hover { color: var(--white); background: var(--primary-dark); }
.menu-toggle { display: none; width: 44px; height: 44px; padding: 0; border: 0; background: transparent; border-radius: 8px; color: var(--text); cursor: pointer; }
.menu-toggle svg { width: 24px; margin: auto; }

.hero { position: relative; overflow: hidden; padding: 92px 0 104px; }
.hero::before { content: ""; position: absolute; width: 480px; height: 480px; right: -220px; top: -220px; border-radius: 50%; background: #eff6ff; z-index: -1; }
.hero-grid { display: grid; grid-template-columns: 1.02fr .98fr; align-items: center; gap: 68px; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; margin-bottom: 20px; padding: 6px 12px; color: var(--primary-dark); background: var(--primary-soft); border-radius: 999px; font-size: 14px; font-weight: 700; }
.eyebrow::before { content: ""; width: 7px; height: 7px; background: var(--primary); border-radius: 50%; }
.hero h1 { margin: 0 0 22px; font-size: clamp(44px, 6vw, 68px); line-height: 1.08; letter-spacing: -.045em; }
.hero h1 span { display: block; margin-top: 12px; font-size: .62em; font-weight: 700; letter-spacing: -.035em; }
.hero-copy { max-width: 560px; margin: 0 0 32px; color: var(--muted); font-size: 18px; }
.hero-copy strong { display: block; margin-bottom: 4px; color: #374151; font-weight: 600; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }

.btn { min-height: 46px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 10px 22px; border: 1px solid transparent; border-radius: 8px; font-weight: 700; cursor: pointer; transition: background .2s, border-color .2s, color .2s, transform .2s; }
.btn:hover { transform: translateY(-1px); }
.btn-primary { color: var(--white); background: var(--primary); }
.btn-primary:hover { color: var(--white); background: var(--primary-dark); }
.btn-secondary { color: #374151; background: var(--white); border-color: var(--border); }
.btn-secondary:hover { color: var(--primary-dark); border-color: #bfdbfe; background: #f8fbff; }
.btn-block { width: 100%; }
.btn:disabled { opacity: .58; cursor: not-allowed; transform: none; }

.network-visual { position: relative; width: min(100%, 470px); aspect-ratio: 1; margin-left: auto; }
.network-shell { position: absolute; inset: 8%; border: 1px solid #dbeafe; border-radius: 50%; background: linear-gradient(145deg, #fff, #f5f9ff); box-shadow: var(--shadow); }
.network-ring { position: absolute; inset: 20%; border: 1px dashed #bfdbfe; border-radius: 50%; }
.network-line { position: absolute; left: 50%; top: 50%; width: 31%; height: 1px; background: #bfdbfe; transform-origin: left; }
.line-1 { transform: rotate(-48deg); }
.line-2 { transform: rotate(24deg); }
.line-3 { transform: rotate(130deg); }
.line-4 { transform: rotate(188deg); }
.network-center { position: absolute; left: 50%; top: 50%; width: 92px; height: 92px; transform: translate(-50%, -50%); display: grid; place-items: center; border: 8px solid #dbeafe; border-radius: 50%; background: var(--primary); color: white; box-shadow: 0 14px 30px rgba(59, 130, 246, .28); }
.network-center svg { width: 38px; }
.node { position: absolute; display: grid; place-items: center; width: 54px; height: 54px; color: var(--primary-dark); background: var(--white); border: 1px solid #dbeafe; border-radius: 16px; box-shadow: 0 10px 26px rgba(30, 64, 175, .1); }
.node svg { width: 25px; }
.node-1 { left: 18%; top: 14%; }
.node-2 { right: 8%; top: 39%; }
.node-3 { left: 20%; bottom: 8%; }
.node-4 { left: 2%; top: 45%; }
.status-pill { position: absolute; right: 8%; bottom: 15%; display: flex; align-items: center; gap: 8px; padding: 10px 14px; background: white; border: 1px solid var(--border); border-radius: 10px; box-shadow: 0 10px 24px rgba(15, 23, 42, .08); color: #374151; font-size: 13px; font-weight: 700; }
.status-pill i { width: 8px; height: 8px; background: #22c55e; border-radius: 50%; }

.feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.feature-card { padding: 30px; background: white; border: 1px solid var(--border); border-radius: 14px; transition: border-color .2s, transform .2s, box-shadow .2s; }
.feature-card:hover { transform: translateY(-3px); border-color: #bfdbfe; box-shadow: 0 14px 34px rgba(15, 23, 42, .06); }
.icon-box { width: 48px; height: 48px; display: grid; place-items: center; margin-bottom: 22px; color: var(--primary); background: var(--primary-soft); border-radius: 12px; }
.icon-box svg { width: 25px; }
.feature-card h3 { margin: 0 0 10px; font-size: 20px; }
.feature-card p { margin: 0; color: var(--muted); font-size: 15px; }

.download-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; }
.download-card { padding: 26px 22px; text-align: center; background: var(--white); border: 1px solid var(--border); border-radius: 14px; }
.platform-icon { width: 52px; height: 52px; display: grid; place-items: center; margin: 0 auto 18px; color: #374151; background: var(--surface); border-radius: 14px; }
.platform-icon svg { width: 28px; height: 28px; }
.download-card h3 { margin: 0 0 6px; font-size: 18px; }
.download-card p { min-height: 48px; margin: 0 0 20px; color: var(--muted); font-size: 14px; }
.download-card .btn { width: 100%; padding-inline: 12px; }

.cta { padding: 0 0 96px; }
.cta-inner { display: flex; align-items: center; justify-content: space-between; gap: 32px; padding: 46px 52px; color: var(--white); background: #172554; border-radius: 18px; }
.cta-inner h2 { margin: 0 0 6px; font-size: clamp(26px, 4vw, 36px); }
.cta-inner p { margin: 0; color: #cbd5e1; }
.cta .btn { flex: 0 0 auto; color: var(--primary-dark); background: white; }
.cta .btn:hover { background: #eff6ff; }

.site-footer { padding: 28px 0; border-top: 1px solid var(--border); }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; color: var(--muted); font-size: 14px; }
.footer-links { display: flex; gap: 24px; }
.footer-links a:hover { color: var(--primary); }
.support-contact a { color: var(--primary-dark); font-weight: 600; }

.toast-container { position: fixed; z-index: 1000; top: 20px; right: 20px; display: grid; gap: 10px; pointer-events: none; }
.toast { min-width: 280px; max-width: min(380px, calc(100vw - 40px)); display: flex; align-items: center; gap: 10px; padding: 13px 16px; color: #374151; background: white; border: 1px solid var(--border); border-left: 4px solid var(--primary); border-radius: 9px; box-shadow: 0 12px 35px rgba(15, 23, 42, .14); opacity: 0; transform: translateY(-10px); transition: opacity .2s, transform .2s; pointer-events: auto; }
.toast.show { opacity: 1; transform: translateY(0); }
.toast-success { border-left-color: var(--success); }
.toast-error { border-left-color: var(--error); }
.toast-icon { flex: 0 0 auto; width: 19px; height: 19px; display: grid; place-items: center; color: white; background: var(--primary); border-radius: 50%; font-size: 12px; font-weight: 800; }
.toast-success .toast-icon { background: var(--success); }
.toast-error .toast-icon { background: var(--error); }

.legal-page { min-height: 100vh; background: var(--surface); }
.legal-header { padding: 22px 0; border-bottom: 1px solid var(--border); background: white; }
.legal-main { padding: 64px 0 90px; }
.legal-card { max-width: 800px; margin: 0 auto; padding: 48px; background: white; border: 1px solid var(--border); border-radius: 14px; }
.legal-card h1 { margin: 0 0 28px; font-size: 36px; line-height: 1.2; }
.legal-card h2 { margin: 28px 0 8px; font-size: 20px; }
.legal-card p, .legal-card li { color: #4b5563; }
.legal-card ul { padding-left: 20px; }
.legal-card .btn { margin-top: 24px; }

@media (max-width: 900px) {
  .hero-grid { gap: 32px; }
  .download-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .container { width: min(calc(100% - 32px), 1120px); }
  .section { padding: 72px 0; }
  .menu-toggle { display: block; }
  .nav-links { position: fixed; inset: 73px 0 auto 0; display: grid; gap: 0; padding: 12px 16px 20px; background: white; border-bottom: 1px solid var(--border); box-shadow: 0 14px 25px rgba(15, 23, 42, .08); opacity: 0; visibility: hidden; transform: translateY(-8px); transition: opacity .2s, transform .2s, visibility .2s; }
  .nav-links.open { opacity: 1; visibility: visible; transform: translateY(0); }
  .nav-links a { padding: 12px 14px; }
  .nav-links .nav-primary { margin-top: 6px; text-align: center; }
  .hero { padding: 64px 0 76px; }
  .hero-grid { grid-template-columns: 1fr; gap: 52px; }
  .hero-content { text-align: center; }
  .hero-copy { margin-inline: auto; }
  .hero-actions { justify-content: center; }
  .network-visual { width: min(100%, 400px); margin: auto; }
  .feature-grid { grid-template-columns: 1fr; }
  .cta { padding-bottom: 72px; }
  .cta-inner { align-items: flex-start; flex-direction: column; padding: 36px 30px; }
  .footer-inner { flex-direction: column; text-align: center; }
  .footer-links { flex-wrap: wrap; justify-content: center; row-gap: 10px; }
  .legal-main { padding: 32px 0 64px; }
  .legal-card { padding: 30px 24px; }
}

@media (max-width: 520px) {
  .hero h1 { font-size: 42px; }
  .hero-actions .btn { width: 100%; }
  .network-center { width: 78px; height: 78px; }
  .node { width: 46px; height: 46px; border-radius: 13px; }
  .download-grid { grid-template-columns: 1fr; }
  .download-card p { min-height: auto; }
  .toast-container { right: 12px; top: 12px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}