What did you find difficult while building the project? By far, the most trouble I had was due to having my components inside the "pages" folder in NextJS. I spent a long time troubleshooting why the build kept crashing until I realized I just had to have a separate folder for my non-page components. Besides that, the replying system took me a while to figure out. But in the end it turned out fine.
Which areas of your code are you unsure of? Passing down props feels a bit overkill at times. Maybe there's a way to limit the amount of props I have to write down. I also haven't managed to give the plus/minus button a change of colour on hover. If someone knows a good way to do this, feel free to let me know.
Do you have any questions about best practices? Regarding the props, I'd say. Passing down a bunch of props through layers of components feels a bit prone to bugs. If there's a better way to manage props, do let me know!