Change to wide layout style

Is it possible to change to wide layout style, i.e. have the theme full width with no background? On mobile devices my website shows up without the background if the device is held vertically, but with background if it is held horizontally. This is not a problem e.g. on an iPad where the width is large enough, but problematic on a mobile phone, because the background on the two sides reduces the main content area. My site is http://www.rehearsalstudioslondon.com/