Css layout 100% height error

my site is appearing differently on different browsers..

the 1st screen should be 100% which is correctly appearing on chrome, safari and IE but not on Firefox.

http://gsevenstudio.com/

Screen looks fine to me in firefox (1920*1080) I even have to scroll down quite a bit.

In your rollover image - second from the bottom, second from the left: Is that supposed to say STLICTLY? Just curious

try to fix with hack..