Ah… thanks for the link. The background is white because the site’s page is full width right now. The only time you see the blue background you set is on a short page like this one: http://markettrendscorp.com/services/
If you want to see the background on other pages, you need to change the full width to a boxed layout. Go to Appearance >> Customize >> Basic Settings >> Choose Boxed Medium under Page Width setting.