<!DOCTYPE html>

<ol>
 <details><summary>summary</summary></details>
 <li value="1">1</li>
 <li value="2">2 <details><summary>summary</summary></details></li>
 <li value="3">3</li>
 <details><summary>summary</summary></details>
 <li value="4">4</li>
</ol>

<ol>
 <summary>summary</summary>
 <li value="1">1</li>
 <li value="2">2 <summary>summary</summary></li>
 <li value="3">3</li>
 <summary>summary</summary>
 <li value="4">4</li>
</ol>

