Space between buttons with Bootstrap 4

[akath20]

There is a small space between the buttons that I can't seem to fix. I have tried many combinations of css but they either result in still having the space, exposing the :after :before elements as a square, or removing the arrow completely.

https://codepen.io/anon/pen/geJqLm

[westonganger]

Bootstrap 4 is based on rem units and this libraries code is based on px. I will have to re-work the CSS to be bootstrap 4 compatible