:root {
  --bg: #fbfbfa;
  --text: #1f2933;
  --muted: #5f6b76;
  --accent: #2455c3;
  --bar: #eef1f4;
  --bar-text: #1f2933;
  --line: #dde1e5;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
}
header {
  padding: 2rem 1rem 1rem;
  text-align: center;
  border-bottom: 1px solid var(--line);
}
header h1 { margin: 0; font-size: 2rem; letter-spacing: -0.01em; }
nav {
  background: var(--bar);
  border-bottom: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.25rem;
  padding: 0.5rem;
}
nav a {
  color: var(--bar-text);
  text-decoration: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
}
nav a:hover, nav a:focus-visible { background: rgba(0,0,0,0.07); }
nav a[aria-current="page"] { background: rgba(0,0,0,0.12); font-weight: 600; }
main { max-width: 42rem; margin: 0 auto; padding: 2rem 1rem 3rem; }
main h2 { margin-top: 0; }
main h3 { margin-top: 2rem; }
a { color: var(--accent); }
footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.875rem;
  padding: 1.5rem 1rem;
  border-top: 1px solid var(--line);
}