card-deck, Mobile screen, Unexpected margins behavior and separations in rows

Created by: IgorPelevanyuk

On narrow screens:

1. It looks like some unnecessary margins(left) appear. (Narrow-medium screen)
2. There is no margins(top, bottom). (Narrow screen)
3. With four cards: three cards on one row, one card on the next row (Narrow-medium screen) Codepen(You will see the bug when squeeze screen horizontally): http://codepen.io/Gavelock/pen/vgMNOx Tested on Mozilla Firefox 53.0a2 (2017-02-05) (64-бит), Linux Ubuntu 16.04 LTS