Omega theme background color problems What would be the best option for achieving following: 

I need to have a background color blue under website and the body of the website (including all regions) would be white. Best for demonstrating would be to visit this site 


  http://www.prevention.com/health/healthy-living/50-healthiest-eco-spas-america


By default alpha-default-normal-12.css contains rule for body min-width: 960px. I can solve it by changing body width to width:960px and adding margin: 0 auto;. 

However after switching to fluid layout, width is taken from my global.css and it of course restricts layout to be fluid. 

My question is what would be best way to achieve this without editing other css files. Or is it ok to edit them?
You can edit global.css insted of editing alpha_default_normal.css so that changes will persists even if you changes your browser resolution. And according to me, set the width of the div in percentage... so it will automatically adjust to other screen resolutions.
eg.

width:70%;
margin : 0 auto;