My first project. Tip calculator, trying to nail every feature

Hi! like I already clearified this is my first project ever, as I started to self teach me about one month and a half ago. Tried to do my best to include every feature, like the reset button beeing disabled, the can't be zero warnings, and overall the calculator working perfectly no matter how you use it. I'm aware there is a problem in height when it comes to tall mobile devices, I'd like to know how that could be solved. And aside of that I'd appreciate any kind of general feedback related to optimization, organization, how do you like my solutions, and any thing you would like to point to me.

Thanks!