How to select the first child element with CSS

Problem: in my markdown file I had the need to style the first ul, the table of contents, and I couldn’t add a class or an id to target it with CSS.

So I looked into how to target it with a selector.

The HTML structure was this:

<div id="content">
    ...the TOC
  </ul> of the HTML

This worked to select the first child of div#content and leave other ul elements unaffected:

div#content > ul:first-of-type { styles