body {
  font-family: system-ui, sans-serif;
  margin: 40px auto;
  max-width: 700px;
  line-height: 1.6;
  color: #111827;
  background: #f9fafb;
}

header, footer {
  text-align: center;
}

nav a {
  text-decoration: none;
  color: #2563eb;
  margin: 0 8px;
}

nav a:hover {
  text-decoration: underline;
}