Three column preview card solution

Hi!

This is the first time that I used SASS and would appreciate some feedback about the structure of it. Is it easy to follow? Were the variables necessary? Because its a small project I wrote variables to practice writing them. And just any advice and/or observations you may have about the project as a whole.

I also coded height: 100vh for the body as a way to use the whole page so I could fit the column card in the middle of the screen. Is there another way to do that or is that a good way?

Thank you