body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  margin: 0;
  padding: 0;
  background: #f4f4f4;
}

header {
  background: #222;
  color: #fff;
  padding: 1rem;
}

header h1 {
  margin: 0 0 0.5rem 0;
}

nav a {
  color: #fff;
  text-decoration: none;
  margin-right: 1rem;
}

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

main {
  padding: 1.5rem;
}

h2 {
  margin-top: 0;
}