Collapsing archives spacing problems

Hi there. I am using the collapsing archives plugin on http://www.geoffholder.com.

However the archives don’t display correctly, 2013 is squashed and I cannot find where to change this in the CSS?

If anyone has any help as to where I can find a fix for this it would be greatly appreciated!

Thank you in advance!

http://ww.wp.xz.cn/plugins/collapsing-archives/