:root {
  --bg: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;
  --link: #111827;
  --link-muted: #374151;
  --maxw: 920px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 18px;
}

.site-header {
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 64px;
  gap: 16px;
}

.site-title {
  font-weight: 700;
  text-decoration: none;
  color: var(--link);
  letter-spacing: 0.2px;
}

.nav {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav-link {
  text-decoration: none;
  color: var(--link-muted);
  padding: 8px 10px;
  border-radius: 10px;
  border: 1px solid transparent;
}

.nav-link:hover {
  border-color: var(--border);
  color: var(--link);
}

.nav-link.active {
  border-color: var(--border);
  color: var(--link);
  background: #f9fafb;
}

.content {
  padding: 28px 0 48px 0;
}

h1 { font-size: 34px; margin: 0 0 10px 0; }
h2 { font-size: 20px; margin: 26px 0 10px 0; }
p { margin: 10px 0; color: var(--text); }
a { color: var(--link); }

.card {
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px 16px;
  background: #ffffff;
}

.muted { color: var(--muted); }

.site-footer {
  border-top: 1px solid var(--border);
  padding: 18px 0;
  color: var(--muted);
}

.footer-inner {
  display: flex;
  gap: 12px;
  justify-content: space-between;
  flex-wrap: wrap;
}

.footer-right a {
  color: var(--muted);
  text-decoration: none;
}

.footer-right a:hover { color: var(--text); }
.dot { padding: 0 8px; color: var(--border); }