Aside: In the table relating n to pi, what’s with the baselines of the text in the second column? (“exact” and “you are here”.) Is some renderer treating the characters like mathematical symbols?

The post is using MathJax. If you long press (presumably right click on desktop?) you get a menu.

If weird fonts bother you, consider disabling custom fonts in your browser settings. I do it occasionally, but it also breaks fontawesome (and similar), so it's not a clear win.