Math isn’t respecting the boundaries of containers

Created by: connerbw

Can someone help me understand what's going on here?

I'm using the defaults, expecting width: "container" to do some magic for me, but it isn't. Any ideas?

Here's the test page:

• https://dactest1.textopress.com/chapter/mathjax-common-html-problems/

(Note to future selves, test page is temporary, will disappear once problem is resolved)