@media print {
  /* … */
}

body {
  display: flex;
  font-family: Arial, sans-serif;
  line-height: 1.3rem;
  margin: 0;
  padding: 0;
}

nav {
  background-color: #271d3d;
  color: white;
  width: 200px;
  position: fixed;
  top: 0;
  left: 0;
  height: 100%;
}

.navbar-header {
  font-size: 1.5em;
  font-weight: bold;
  color: whitesmoke;
  margin: 10px 0 10px 10px;
}

.nav-link {
  display: block;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.1rem;
  color: white;
  transition: background-color 0.3s;
  position: relative;
}

a {
  border-top: 1px solid white;
  padding: 10px;
}

a:last-child {
  border-bottom: 1px solid white;
}

.nav-link:hover {
  background-color: #555;
}

main {
  margin-left: 250px;
  padding: 20px 40px 0 20px;
}

.main-section {
  margin-bottom: 40px;
}

header {
  font-size: 2em;
  margin-bottom: 20px;
}

p {
  line-height: 1.8rem;
  margin-bottom: 20px;
}

span {
  font-weight: bold;
  font-size: 1.1rem;
  text-decoration: underline;
}

.code-caveat {
  font-weight: normal;
  font-size: 0.75rem;
  text-decoration: none;
  font-style: italic;
}

code {
  display: block;
  background-color: #f7f7f7;
  border-radius: 4px;
  margin: 20px;
  padding: 15px;
}

li {
  margin: 10px 0 5px 20px;
  list-style: circle;
}