Slider and Footer background

Hi,

I am desıgnıng my own theme but unfortunately I stuck in a point which is assigning a background to back of the slider that I wanna create. I mean not on all the page, I just wanna assign a background according to slider's height. So what I want is giving witdh 100%, then assign a background to it and place it to the center of it.

I also wanna do the same thing for footer section. I mean to put a 100% witdh to the back of a 980px footer.

Thank you, I am working on opencart default theme and waiting for your help.