Can't input text in HTML lessons

For the previous lessons, I was unable to input any text unless I first moved the cursor with the arrow keys.

This worked fine until I got to the second to last lesson, which has the user start with a blank document. Now I can not enter any text whatsoever. I’ve tried refreshing the page and disabling my extensions, but nothing has worked.

I’m using Chrome, btw.

EDIT: Switched to Firefox and worked fine.