Mais cette grid impose de rajouter la class last sur la dernière colonne, pour éviter cette chose ignoble, il suffit de remplacer ceci
.col1.last, .col2.last, .col3.last, .col4.last, .col5.last, .col6.last, .col7.last, .col8.last, .col9.last, .col10.last, .col11.last, .col12 { margin: 0; }
Par ceci
.col1:last-child, .col2:last-child, .col3:last-child, .col4:last-child, .col5:last-child, .col6:last-child, .col7:last-child, .col8:last-child, .col9:last-child, .col10:last-child, .col11:last-child, .col12 { margin: 0; }