Use Sass @while syntax to build grid layout in project Javascript Calculator

Hi. I’m working on the CSS part of the Javascript Calculator test.
I’m trying to use Sass @while syntax in order to build a grid, similarly to the example showed in the Saas course. However, I’m obviousy not doing it the right way as the classes col-xxx and row-xxx I’ve defined this way don’t seem to be used at all.
Could someone please help me out?
Here’s the CodePen url: https://codepen.io/GStucki/pen/jENmzNM