How should i assign a counters() to the content property?

[171h]

like this: https://developer.mozilla.org/en-US/docs/Web/CSS/counters

<ol>
  <li>
    <ol>
      <li></li>
      <li></li>
      <li></li>
    </ol>
  </li>
  <li></li>
  <li></li>
  <li>
    <ol>
      <li></li>
      <li>
        <ol>
          <li></li>
          <li></li>
          <li></li>
        </ol>
      </li>
    </ol>
  </li>
</ol>

ol {
  counter-reset: listCounter;
}
li {
  counter-increment: listCounter;
}
li::marker {
  content: counters(listCounter, ".", upper-roman) ") ";
}
li::before {
  content: counters(listCounter, ".") " == " counters(
      listCounter,
      ".",
      lower-roman
    );
}