Social Proof - Mobile first, SCSS, Grid, Flexbox

I'm decided to incorporate SCSS with this challenge (and future challenges going forward). I tried using mixins and an extension, just for practice. I really like the nesting capability.

I had some trouble with the background-image again. I wasn't quite sure on the framing of it all. I measured the height/width of the entire desktop image to bet 800x1440. All of the content measured out to be about 556x1100. I think I messed up and set the social-proof div to 800x1100 with padding, but in reality I should probably have set the social-proof div to 800x1100. If anyone has best practices on this or corrections for me, send them my way!