NOTE: This is a very basic theme. It has very limited use so it's not designed for just any old site. See the documentation page for a Facebook app you can use with this theme.
This theme came about because I wanted to offer a contact form on my Facebook page using an iFrame, but didn't want to clutter up the form with the header and footer of my theme. So I created The Void. It has no header, it has no footer and has no styles (except for some basic colour options) so you can seamlessly integrate it with not only Facebook pages, but any kind of page where you need to pull pages from your own site (or another site you run) without having to worry about styles.
To see an example, check out https://www.facebook.com/davidgrayphotography?sk=app_211427168875708 which is an iFrame that points to my C5 powered website running this theme. To the end user, they don't notice that the form comes from another site.
If you've found The Void useful, you'd be an even awesome-er person if you bought me a beer via PayPal! My address is grayda [at] solidinc [dot] org