problem with masterpage

Hi everybody.
I have a masterpage like this.I use table for header and footer(blue color).I want to use a color or background image for my page (red color).but when I select a color , the contentplaceholder and contents in other page has the color I selected for background.I want the color of the contentplaceholder and contents be white(with no color).like this picture.
what should I do?
 
...