I added some code to change the color of the cards accordingly to how the user has learned the card. Its specifically for the use of when the user has many cards and they can quickly see which ones they need to learn or review.
The code is linked to the "learned, needs review, and not learned" buttons on the review card.
Also added code to change the color of the card as you are making them.
I commented all the code incase you want to change the colors or take it out completely.