JSFiddle - React, Tailwind, and code Playground

HTML

<div>
  <p>aaa</p>
  <p>bbb</p>
</div>
<hr />
<div>
  <p>aaa</p>
  <p>bbb</p>
</div>

CSS

p::before {
  content: counter(c) '/ ';
  counter-increment: c 1;
}
div ~ div::before {
  content: counter(c, none);
}