[Theme: Greyzed] background image

Love this theme but have a questions about the background image, hopefully someone can help. The background image and the content boxes line up perfectly as long as the browser is wide enough. If the browser is too narrow then the background and the content box do not line up anymore. These are not lined up if looking at the site on an ipad. Is there anyway to fix this? My site is criggers.com , thanks.

https://www.ads-software.com/extend/themes/greyzed/