body {
  max-width: 40em;
  line-height: 1.6;
  margin: 0 auto;
  padding: 0.5em;
  color: #333;
  font-family: "Helvetica", "Arial", sans-serif;
}
h1, h2, h3 {
  line-height: 1.2;
}
@media print {
  body {
    line-height: 1.4;
  }
}