With the code you posted in this thread paired with the proper markup, below a viewport width of 640px the column will be hard against the left edge, with a double gap (or a bit more, depending on font metrics) on the right.

The problem is you’ve put this inside a container that already has a side gap, which is not how it was supposed to be used. Inspect the grid tracks on the original article at various viewport sizes. Full bleed means that the item goes right to the edge of the viewport.