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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: #fafafa;
  color: #222;
  line-height: 1.6;
  padding: 2rem;
  max-width: 720px;
  margin: 0 auto;
}

header {
  border-bottom: 1px solid #e0e0e0;
  padding-bottom: 1rem;
  margin-bottom: 2rem;
}

h1 { font-size: 1.75rem; margin-bottom: 0.5rem; }
h2 { font-size: 1.25rem; margin: 1rem 0 0.5rem; }
h3 { font-size: 1.05rem; margin: 0.5rem 0; }

nav a {
  color: #0066cc;
  text-decoration: none;
  margin-right: 1rem;
}
nav a:hover { text-decoration: underline; }

main section, main article { margin-bottom: 1.5rem; }

.hero {
  background: #fff;
  padding: 1.5rem;
  border-radius: 4px;
  border: 1px solid #eee;
}

footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid #e0e0e0;
  color: #888;
  font-size: 0.875rem;
}