Add option to center elements in final grid row

In cases where an archive loop with a three- or four-column grid has less than the maximum no. of items in the final row, add an option to center those items. Maybe it’s just me but when you have one or two items in a four-column grid and they are flush left, it seems like it would look a lot better to center them below the prior row. In fact, if a three- or four-column grid returns less than the max items in the initial row, there should be a way to center those as well. With grid, the CSS required can be pretty complex to achieve this, and I am still struggling to make this work on my end. Thanks for listening.