Fix the visuals for the card components on the question previews

The card components related to issue https://gitlab.com/worcester/cs/naturalization-interview-confidence-environment/demo-react/-/issues/41 show up in such a way that the cards are blended with each other instead of showing as individual cards. We want to fix the style of the Cards.js page so that each card is padded properly and doesn't merge with other cards.