:root {
  --bg: #fafaf9;
  --bg-alt: #f2f4f3;
  --fg: #1a1d1c;
  --fg-muted: #5c6560;
  --accent: #16a37a;
  --accent-dark: #0f7d5c;
  --border: #e2e5e3;
  --mono: "JetBrains Mono", "SF Mono", Consolas, "Courier New", monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  --radius: 10px;
  --max-w: 1120px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  font-size: 16px;
}

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

a { color: inherit; text-decoration: none; }

/* header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(250, 250, 249, 0.9);
  backdrop-filter: blur(6px);
  position: sticky;
  top: 0;
  z-index: 10;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo-img { height: 30px; display: block; }

.site-nav { display: flex; gap: 28px; }

.site-nav a {
  font-size: 14px;
  font-weight: 500;
  color: var(--fg-muted);
  transition: color .15s;
}

.site-nav a:hover { color: var(--accent-dark); }

.lang-toggle {
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 600;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--fg);
  padding: 6px 12px;
  border-radius: 999px;
  cursor: pointer;
  transition: border-color .15s, color .15s;
}

.lang-toggle:hover { border-color: var(--accent); color: var(--accent-dark); }

/* hero */
.hero { padding: 88px 0 72px; }

.hero-inner {
  display: flex;
  align-items: center;
  gap: 48px;
}

.hero-copy { flex: 1.1; }
.hero-art { flex: 1; display: flex; justify-content: center; }
.hero-art img { width: 100%; max-width: 380px; }

.eyebrow {
  font-family: var(--mono);
  font-size: 13px;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--accent-dark);
  margin-bottom: 14px;
}

.hero h1 {
  font-size: 44px;
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 18px;
}

.hero-sub {
  font-size: 17px;
  color: var(--fg-muted);
  max-width: 480px;
  margin-bottom: 30px;
}

.hero-actions { display: flex; gap: 14px; }

.btn {
  display: inline-block;
  padding: 12px 22px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 600;
  transition: transform .15s, opacity .15s;
}
.btn:hover { transform: translateY(-1px); }

.btn-primary { background: var(--fg); color: var(--bg); }
.btn-primary:hover { background: var(--accent-dark); }

.btn-ghost { border: 1px solid var(--border); color: var(--fg); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent-dark); }

/* features */
.features { padding: 8px 0 64px; }

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px;
  transition: border-color .15s, transform .15s;
}
.feature-card:hover { border-color: var(--accent); transform: translateY(-2px); }

.feature-icon { width: 32px; height: 32px; margin-bottom: 14px; }

.feature-card h3 { font-size: 17px; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: var(--fg-muted); }

/* subsites / nav section */
.nav-section {
  background: var(--bg-alt);
  padding: 64px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.nav-section h2 { font-size: 26px; margin-bottom: 8px; }
.section-sub { color: var(--fg-muted); font-size: 15px; margin-bottom: 32px; }

.subsite-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.subsite-card {
  background: #fff;
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  padding: 22px;
}

.badge {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .04em;
  text-transform: uppercase;
  background: var(--accent);
  color: #fff;
  padding: 3px 9px;
  border-radius: 999px;
  margin-bottom: 10px;
}

.subsite-card h3 { font-size: 15px; margin-bottom: 6px; }
.subsite-card p { font-size: 13px; color: var(--fg-muted); }

/* about */
.about { padding: 72px 0; }
.about-inner { max-width: 640px; }
.about h2 { font-size: 24px; margin-bottom: 16px; }
.about p { color: var(--fg-muted); margin-bottom: 12px; font-size: 15px; }

/* footer */
.site-footer { border-top: 1px solid var(--border); padding: 28px 0; }
.footer-inner {
  display: flex;
  justify-content: space-between;
  font-size: 13px;
  color: var(--fg-muted);
}
.footer-domain { font-family: var(--mono); }

@media (max-width: 760px) {
  .site-nav { display: none; }
  .hero-inner { flex-direction: column; }
  .hero h1 { font-size: 32px; }
  .feature-grid { grid-template-columns: 1fr; }
}