Default Background Color in Body

I use a theme switcher on my site which sends mobile and tablet visitors to the Clear Retina theme. When I view the theme on my desktop in test mode it shows me a white background with grey header and footer areas. However, on mobile devices it appears to be a light grey.

I’d like to have the content area be pure white to match my Adsense backgrounds. Am I crazy or is the background light grey? I haven’t been able to find the CSS styling with the Inspect Element tool. Thanks