Background color

One of my students had a friend change his background color. Now when you type in a formula, the parenthesis and absolute value signs aren’t visible. How do I reset the background so these are visible again? The students use chrome books.

Some of my students insist on using dark mode on their chromebooks, so the screen is black. I’ve noticed it makes things difficult to see in Desmos. If this is the culprit, ask your student to change it back under Personalization in Settings. Otherwise, you can shutdown the computer, then hold down the refresh key while it is booting up. Let it go when you see the chrome logo booting up, then it will restore factory settings.