Cannot Change mod buttons using custom css

Please see the below css

div#fd.eb .mod-btn-primary:hover, div#fd.eb .mod-btn-primary:focus, div#fd.eb .mod-btn-primary:active, div#fd.eb .mod-btn-primary.active, .open .dropdown-toggle_div#fd.eb .mod-btn-primary

I am unable to change the button co,lors on the NICKEL theme as the buttons are coded as important. I dont mind canging the css in the style sheet however if you update the stylesheet in the future then changes that I make will dissapear.

http://www.polarchoice.com/en/blog

If you click the login button its blue I need to change its style