Change container colour on homepage

Hi

Im looking to change the central container box on the homepage’s colour to match my background colour – would you tell me where you do this since style.css is no longer used?

Also, even though I set my configuration to fullscreen, no columns, Im still getting background and the central slider does not stretch across the screen. Is there something else I should be changing?

Webpage is http://www.videyoh.com

Thanks