Nice article!
i would like to use responsive sprites in a project at our company, but i have encountered a problem with rounding of the background-postition. I forked your pen (http://codepen.io/anon/pen/zGvOZV) and put in our testing sprites and like you can see, when the sprites container is not exactly the width of one frame, the entire frame moves up and down by one pixel. I was wondering if you had an Idea how this could be fixed.
Thanks in advance