how do i do a dropdown that is like this?

I realize I'm a bit late, but found this post while trying to figure out how to code dropdowns as well. I managed to find out how to do it and figured I'd share:

<details>

   <summary>title</summary>

   <p>contents</p>

 </details>

"details" is what creates the dropdown, "summary" is the label shown next to it, and "p" is the contents

found out before you commented on it, thanks still!