Mortgage Calculator (SASS + JS)

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

I am most proud of my JS and the logic. It was hard in the beginning but I am slowly getting the hang out it. Next time I will try to make sure that the code I write is concise and group more of my code into functions to make sure it's more reusable.

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

A challenge I encountered was the formula for the repayment option. Googling the answer helped.

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

Any feedback is welcome! How can I make my code more readable and reusable?