body {
  font-family: sans-serif;
  max-width: 700px;
  margin: 2em auto;
  background-color: #fefefe;
  color: #222;
  line-height: 1.6;
}
header, footer {
  text-align: center;
  margin-bottom: 2em;
}
nav a {
  margin: 0 0.5em;
  text-decoration: none;
  color: #0055aa;
}
nav a:hover {
  text-decoration: underline;
}