applying border to color elements results in float layout breaking

[marcelmoreau]

Tell us about the issue you are experiencing

I am laying out a grayscale color palette. The floats are not working as expected due to a border being applied to a light color shade's container. This makes its element 2 pixels taller than other colors. I have made said border blue in my example screenshot. Consider using an inset box-shadow instead of border for the next release. This will not add to its height like a border does.

What behaviour would you expect?

How can this issue be replicated?

Screenshots / Screencast

Your environment

Platform:
OS Version: Sierra 10.12.6
Node Version: 9.3.0
NPM Version: 5.6.0
Astrum Version: 1.9.5