Mystique – Connecting sidebar to the footer

I have Mystique 3.2.9.3 installed (WordPress 3.3.2). I used this code to color the sidebar in different color than the content area:

.c2right #mask-1,
.c2left #mask-3,
.c3 #mask-2,
.c3left #mask-3,
.c3right #mask-1
  {background: #fff;}

.c2left #mask-1,
.c2right #mask-3,
.c3 #mask-1, .c3 #mask-3,
.c3left #mask-2,
.c3right #mask-3
  {background: #eee;}

Only problem is, the sidebar (at the bottom) is not connected to the footer; there’s a white space/gap between the sidebar and the footer. Is there a way to fix this and make the sidebar gray all the way to the footer?

Site is: gbzidan.com