body {
  display: flex;
  min-height: 100vh;
  flex-direction: column;
}
div.content {
  flex: 1;
}
header > nav {
  padding-top: 0.5em;
  padding-bottom: 0.5em;
  margin-bottom: 1.5em;
}
nav.toc {
  float: right;
  border: 1px solid;
  padding-top: 0.5em;
  padding-left: 2em;
  padding-right: 2em;
  margin-bottom: 2em;
  display: block;
}
nav.toc > h3 {
  margin-top: 0.5em;
  margin-bottom: 0.5em;
}

nav.toc > ul {
  margin-top: 0.5em;
}