This seems to be easy for experts. Just post a private message, then I will tell you the model website, and you can then bid.
Also, I will tell you many bbpress mobile optimization plugins so that you can get hints from them.
I want to make a very simple mobile optimization of a bbpress forum such as http://bbpress.dave-wood.org/
This is not my own forum, but my forum looks just like this.
All you need to do is to ensure that
“the screen width of smartphone = width of the forum”
…
