Vintage Calculator of your dreams! (with react, typescript, sass)

Kinda proud of this one. In the previous challenge I encountered strange(for me) behaviour of type=number inputs with react+ts, and this time I decided to do all validations manually. It ended up pretty wild, I basically hardcoded every button's behaviour in every situation following my idea of how a real calculator should behave. I like how it came together, this is not the code to be proud of, but it does the job well! I could find only one sequence of actions that lead to NaN on the calculator screen, and it's not a straightforward one(can you find it?)

The stuff I wanted, but failed to implement:

• Make screen overflow to the left and stay aligned to the right when there are lengthy numbers. It's working now with justify-content: flex-end but for some reason it's not scrollable with flex. Without flex, overflow: auto does it's job, but it overflows to the right despite that the content is aligned to the right. I tried approaches with direction: rtl - no luck, I tried scrollIntoView - it kinda does the job, but it also scrolls vertically and that's bad UX in my opinion. I went with flex in the end.
• Issue related to the previous one - what to do with number with a lot of digits? Given that I chose flex with no scroll I decided to round decimals to 12 digits so a number like 0.333(3) is visible on the screen. It doesn't work for big numbers but it's something. I also made the screen expandable into two lines when there are long numbers, not sure about this decision.
• How to handle all ⌨keyboard 👇events of the whole page? Now keyhandler is on the main div, but if we click away it loses focus. We can't put a keyhandler on the body, can we?

That was a great challenge which I really enjoyed, I appreciate any feedback!