The Mocksup admin has two views: the "sidebar view" and the "dialog view". In total, 15 color values can be changed across both views.
As you enter your colors, the small previews will update to give you an idea of what things will look like once you save.
When this level of color modification is combined with the ability to upload your own logo, favicon, customize the admin copy and even set your own subdomain, you can truly make Mocksup your own.