hierarchical_numbered_lists.css

/* Trick from: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Lists_and_Counters/Using_CSS_counters */
/*
    Unfortunately, this solution is not mixable with <ul> yet,
    so to not break things, let's make it optional by using a custom tag
    around the ordered list of we need it.
 */
nestednumerationlist ol {
    counter-reset: section;
    list-style-type: none;
}

nestednumerationlist ol > li::before {
    counter-increment: section;
    content: counters(section, ".") ". ";
}