I’m probably going to get flack for this because customization is not part of theme support…..however, the problem is how the theme structure was done, this one is a bit difficult. You have to make your page background white, then add a margin bottom to your showcase wrapper, then you can add your shadow. Otherwise, you will have to add a div container full width below the showcase wrapper and use a repeating shadow image…..the rest will have to be up to you 😛
