I've pushed to my fork of fortress commander on my personal github a branch with my first proposed changes to the Fortress UI.
https://github.com/dashorst/directory-fortress-commander/tree/bootstrappify (the list of the commits can be found here: https://github.com/dashorst/directory-fortress-commander/commits/bootstrappify) The first (and currently only) thing I've modified is the login page. All other pages are still empty. You can see the login page here: http://pasteboard.co/5WoHYnb4y.jpg It is but one of (currently) 3 possible backgrounds of castles (Fortresses) that I've found and are license compatible (Creative Commons Zero, from unsplash.com). The login page is responsive and will scale to fit the inputs on your small or large device. I hope this is to your liking. Feel free to comment on the code, formatting, etc. Martijn
