So this is something that I implemented into the quiz engine without fully knowing how it works. And whenever I do that, I always make a to-do for myself to go back and actually research it. Because otherwise, you end up with portions of your code base that you, yourself, don't understand. And I hate that. So it took me a little while to figure this out, but I'll explain it to you. We'll take this in steps. First, I'll hide the HTML, and we'll say, right here, I want to add a background image.