Code History button color changes

Hello, friends.
I’ve been trying to figure out how to change the background color of the app along with the buttons (right answer - green, wrong answer - red) and even looked up the code to see what I was doing wrong. My code looks exactly like the one provided by Codecademy yet the code is still not working the way that its supposed to.
The buttons also keep showing up in the preview as vertically stacked even though they are supposed to be horizontally stacked.

Can anyone see anything I’m doing wrong? Thanks in advance!

Here’s the lesson I was doing: https://www.codecademy.com/paths/ios-developer/tracks/building-code-history-part-one-swiftui/modules/building-the-question-model-swiftui/articles/updating-the-user-interface-swiftui