body {
  counter-reset: h2counter;
}
h2 {
  counter-reset: h3counter;
}
h3 {
  counter-reset: h4counter;
}
h4 {
  counter-reset: h5counter;
}

article.content[autonumbering] h2::before {
  counter-increment: h2counter;
  content: counter(h2counter) ". ";
}
article.content[autonumbering] h3::before {
  counter-increment: h3counter;
  content: counter(h2counter) "." counter(h3counter) ". ";
}
article.content[autonumbering] h4::before {
  counter-increment: h4counter;
  content: counter(h2counter) "." counter(h3counter) "." counter(h4counter) ". ";
}

.toc {
  font-size: 13px;
}

.toc[autonumbering] ol {
  counter-reset: item;
}

.toc[autonumbering] ol > li {
  counter-increment: item;
}

.toc[autonumbering] ol ol > li {
  display: block;
}

.toc[autonumbering] ol ol > li:before {
  content: counters(item, ".") ". ";
  margin-left: -20px;
}