:root {
  --fg: #1a1a1a;
  --bg: #fdfdfd;
  --muted: #666;
  --accent: #0057ff;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.6;
}

body {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1.25rem 4rem;
}

header nav {
  display: flex;
  gap: 1.25rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid #eee;
  margin-bottom: 2rem;
}

header nav a {
  color: var(--fg);
  text-decoration: none;
  font-weight: 500;
}

header nav a:hover { color: var(--accent); }

main h1 { margin-top: 0; }

a { color: var(--accent); }

footer {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid #eee;
  color: var(--muted);
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #eee;
    --bg: #161616;
    --muted: #999;
    --accent: #6ea8ff;
  }
  header nav, footer { border-color: #2a2a2a; }
}