Digital Calculator using vanilla JavaScript

Hello People! I have completed this cool project and have the following few queries:

1- For styling the project, I have used lots of utility classes which is inspiration from Kavin Powell recent project. I wanted feedback if I have used these class effectively. PS: I had approached this project as if it was a multipage website that's why I choose the path to use utility classes.

2- Secondly, I want feedback if my JavaScript code is robust and well written.

Any feedback for improvement will be appreciated. Thanks and regards, Adil