I'm in process of adding responsive design to all my phpBB styles. Today 2 styles are ready for release: Air and Deluxe. What does "responsive design" mean? It means style automatically adjusts itself for any screen resolution, which means users on mobile devices will be able to use style but it will look a bit different. You no longer have to install separate mobile style if you are using one of responsive phpBB styles. So far only Air and Deluxe styles are available. Other styles will be made responsive soon. Downloads: Air style Deluxe style Screenshots below.
Elegance phpBB 3 style is now also responsive. New version is currently available only at GitHub. Download it here: https://github.com/cyberalien/phpbb_styles/tree/elegance/style (click "Download Zip" button on bottom right)