On tablet down the grid collapses and stack on top of each other. This leads to the content of columns inside a row having no spacing between them.
I notice on the project site (http://shelvesgrid.org/) there is extra styling:
[class*="column-"] {
margin-bottom: 1.47059em;
}
Which must be local to the site as it is not included in the grid itself. I have had to add this locally to our framework. But it would be nice to have this out of the box.