body {
  margin: auto;
  max-width: 87ex;
  line-height: 1.5;
  font-family: sans-serif;
}

h1, h2, h3 {
  font-weight: normal;
}

pre, code {
  font-family: x, monospace;
}

pre {
  padding: 1ex;
  background: #eee;
  border: solid 1px #ddd;
  min-width: 0;
  font-size: 90%;
}

code {
  color: #007;
}

div.chapter {
  margin-top: 4em;
  border-top: solid 2px black;
}

p {
  margin-top: 0;
}