<details> <summary>Click to reveal more</summary> <p>This is the hidden content that will be displayed when the user clicks the summary.</p> </details><details> <summary>Table of Contents</summary> <ul> <li> <a href="#web-dev">Web Development</a> </li> <ul> <li><a href="#web-dev-html">HTML</a></li> <li><a href="#web-dev-css">CSS</a></li> </ul> </ul> </details>