body {
  max-width: 700px;
  margin: 40px auto;
  padding: 0 20px;
  font-family: serif;
  line-height: 1.6;
}

a {
  color: inherit;
}

nav {
  border-bottom: 1px solid #ddd;
  padding-bottom: 12px;
  margin-bottom: 40px;
}

nav a {
  margin-right: 12px;
  padding: 6px 10px;
  text-decoration: none;
  border-radius: 4px;
}

nav a:hover {
  background: #f0f0f0;
}