:root {
  --bg: #f7fafc;
  --text: #0f172a;
  --accent: #2563eb;
  --muted: #6b7280;
  --maxw: 900px;
}
* {box-sizing:border-box}
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  margin:0;
  background:var(--bg);
  color:var(--text);
  line-height:1.5;
  display:flex;
  align-items:flex-start;
  justify-content:center;
  padding:32px;
}
main, header, footer { max-width:var(--maxw); width:100% }
header { margin-bottom:24px }
h1 { margin:0 0 8px 0; color:var(--accent) }
a { color:var(--accent); text-decoration:none }
section { background:white; padding:18px; border-radius:8px; margin-bottom:12px; box-shadow:0 1px 3px rgba(2,6,23,0.06) }
footer { color:var(--muted); font-size:0.9rem; margin-top:8px; text-align:center }