Responsive Calculator App Using Javascript

What are you most proud of, and what would you do differently next time?

I'm really happy about how simple the code is, I used Vanilla JS to build the functionality of changing the theme to any of the three (just like the design).

I started with working on the HTML and CSS to have a functional calculator before worrying about the themes. If I have a similar project to this in the future, I would still take this approach.

Overall, I really like how easy the code is, and how fast I was able to build it.

What challenges did you encounter, and how did you overcome them?

I did not encounter any particular issues in the course of solving this.

What specific areas of your project would you like help with?

The Javascript portion for sure. I believe the code would have been even easier if I had knowledge of React JS