Hi @Quentin,
For responsive design, we’re focusing our effort on OJS 3.0, which will be released this year. See e.g. this blog post:
Meanwhile, this thread is about a 3rd-party effort; we heartily encourage this kind of work but don’t directly maintain it ourselves. It’s part of the open-source community.
See also this work, which seems to be written as a plugin for easy installation: http://forum.pkp.sfu.ca/t/responsive-theme-providers
Regards,
Alec Smecher
Public Knowledge Project Team