Unreadable text when you hover it the mouse

When you move the mouse over the number of comments the text becomes unreadable. Screenshot: https://lh5.googleusercontent.com/-3Zm547zH6Zk/UQQ3KsdeIWI/AAAAAAAAHA0/Kmts5bSEMPs/s800/text.png Example: http://fansite.xaa.pl/blog/2013/01/26/osmy-turniej-przed-nami/