I made this using plain CSS.
and the CSS:
I used a wrapper around, and then inside it is the main div, that’s 100% width but with 2.6em in margin.
The boxes are using a width of 27%, its not 33% as you’ll expect because the margin has to have some space, and that’s the problem. The margin on the boxes is not constantly 2.6em. I hope you’ll find out of it, this is the best I could do for now.