Calculator App using CSS Grid, JS

What are you most proud of, and what would you do differently next time?

Well, firstly I made a lot of mistakes and I fixed all of them. At the end I understood that this I actually made core mistake and made this challenge with flexbox and made it with Grid afterwards! During this time, I had some issues but really, I learnt a lot and that's my biggest proud about this challenge. What would I do differently? Well, read description next time so I don't make grid challenge with flexbox :D

What challenges did you encounter, and how did you overcome them?

Being honestly, a lot of them. From learning CSS Grid from scratch to JS methods and functions. Also, huge point here is understanding of balance between CSS and JS. Where should I use CSS or JS, or maybe both. Stuff like that.

What specific areas of your project would you like help with?

I want to have reviews on it since I spend a lot of time on it, so I want to see feedback. Even if it's negative, I just want to learn and if there is anything I could do better at this point, I just want to know it :D