Please Help make a CodePen Responsive

I found this javascript shopping cart CodePen which looks very nice, but I can’t make it responsive in Bootstrap 4.

Only putting it into a <container-fluid> kind of works, but I don’t want full screen width on desktop.

Any help to get this done properly would be great.

… thanks for your reply.
I tried to integrate <div class="row"> <div class="col-md-3"> <div class="col-md-9"> but can’t make it work.
Seems I’m not advanced enough to do this on my own.
Thanks again …