tip-calculator-main-app with currency selector and dark mode

I decided to take this one a bit further and implement currency selection as well as dark mode. Had a lot of fun with this challenge and it's a first one where I actually added my own "touch".

Had one issue where I was not able to use getElementsByClassName to select multiple elements with same class names. querySelectorAll also did not work. Not sure why.

I know there is a lot of improvements to be done for my JS code in order to "clean it" up a bit but I tried my best to obey DRY rule :)