Change overall background color to match react components

[twells46]

Fixes #499. I simply changed the styling to make the background for html and body elements to match what all the react containers are using.

[navzam]

This may fix the problem visually, but I think elements flowing out of the body isn't great and could cause other problems later

[twells46]

I see what you mean, I'll take another look and try to fix the actual problem.

[twells46]

Fixed by using minHeight instead of height for Container and CardContainer and giving the menu cards a minHeight as well. This should be ready to go now.