I am trying tidy up a Grid System element with some nested cells that I have on a full width page. The code is attached. What I'm having difficulty with is reducing the spacing between the rows (see picture). Can't seem to track down what I need to adjust. Having read the documentation I am thinking that the CSS classes .zmb and .zmt may hold the answer, however I have been able to get this functioning - maybe someone would be so kind to give an example of there usage.