CSS Firefox Issue, button clickable only in half

Question

Why when looking this button in order overview you can click only on half of it in Firefox(in other browsers its working fine).

Sorry, I don't know how to replicate the issue, but link is here (but you have to first add to cart something): http://ilovedesign.sk/kosik

Answer 1

Remove this style:

span#confirmbtn { left: -50%; }

And then add this one:

#confirmbtn_button { transform: translateX(-50%); }