> I’ve put a little system in place where, instead of margin-right:20px;, the grid items have a margin-left:20px; applied. This pushes them all a little too far

> I’ve put a little system in place where, instead of margin-right:20px;, the grid items have a margin-left:20px; applied. This pushes them all a little too far across but doesn’t break if you put them in a container that is 20px too wide. Then, once all that’s happened you pull the container back by 20px. That doesn't really make sense to me. Why not just use :last-child, and use a JS fallback if you really want to support browsers that don't support that?