Stats preview card (CSS variables, BEM, responsive)

Hello!

This was a nice step up in challenge to work on with creating a nice transition between mobile and desktop view. However I'm not confident my solution to the challenge is an ideal one. I would appreciate feedback on the following concerns.

-Is my transition from mobile to desktop view something that would be considered valid or appropriate for the challenge? I felt I struggled to figure out how much to let the mobile view grow before transitioning into the desktop view, or maybe I shouldn't have let it grow at all. My aim was to created something that flowed easily between views without resorting to horizontal scrolling.

-Are my uses of "custom" breakpoints likewise valid or appropriate? I know the challenge only called for a mobile and desktop view, but in my attempts to create a smooth transition I felt I needed a 3rd "tablet-like" view to make it work. Unfortunately I couldn't get a more common size to work so I used an uncommon size.

-Is it good practice to always split up a css file into reset, variables etc., and if so what is a good approach to doing this? Although I didn't use it on this project, I think SASS is something that can handle this well from what I understand. Is there vanilla css ways of accomplishing this other than linking every stylesheet which I've heard isn't optimal?

Any and all feedback would be most appreciated of course. Thank you for checking out my solution!