This project utilizes a lot of complex CSS. For the CSS rules, I referred to one video in Kent C Dodds's course on React and made it work for my case. I thought adding a confetti (that is toggled on hover) would be a great way to enhance the experience so I looked for a confetti library, and it turned out successful.
I didn't spend too much time trying to understand every single CSS rule because there were too many and I didn't have the time. I wish to come back to this project with fresh eyes when my vanilla CSS skills have vastly improved.