元素（按钮）之间的空间是否为“margin：0”？

https://jsfiddle.net/TRVfh/2/

A picture:

So, right now, there is a little gam in between the two buttons. and I'd like the buttons to share the middle edge, or at least be touching (if they are touching, changing the CSS so it looks like they are sharing an edge isn't hard)S