Format ordered lists in contract format. 1 > 1.1 > 1.1.a

contract-numerical-formatting-style.css

ol {
  list-style-type: none;
  counter-reset: custom-counter;
}

ol li {
  counter-increment: custom-counter;
}

ol li::before {
  content: counter(custom-counter) ". ";
}

ol ol {
  counter-reset: nested-counter;
}

ol ol li {
  counter-increment: nested-counter;
}

ol ol li::before {
  content: counter(custom-counter) "." counter(nested-counter) ". ";
}

ol ol ol {
  counter-reset: third-level-counter;
}

ol ol ol li {
  counter-increment: third-level-counter;
}

ol ol ol li::before {
  content: counter(custom-counter) "." counter(nested-counter) "."
    counter(third-level-counter, lower-alpha) ". ";
  margin-left: 0;
}

If you are using this in a CKEditor field, add .ck.ck-content to the beginning of each style, like this:

.ck.ck-content ol {
  list-style-type: none;
  counter-reset: custom-counter;
}