body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  margin: 2rem auto;
  max-width: 700px;
  padding: 0 1rem;
  line-height: 1.6;
  color: #333;
  background-color: #fff;
}
h1, h2 {
  color: #111;
}
a {
  color: #0066cc;
  text-decoration: none;
}
nav {
  margin-bottom: 2rem;
}