Create a Mobile Website

I want to build a customized web-based discussion platform, where 2 individuals will be able to communicate and resolve their differences. Please check out: Letusalign.com. The picture shown there is that of a mobile app. But in order to control costs, I have decided to build a mobile website, instead of an App. I have visualized this platform as a forum kind of the tool, with following features: - Sign up/Login (using email, etc.) - Email-based Activation for New User - A page for user to set his password - Option to recover forgotten Password - A page showing list of currently open Topics - A button to start a new discussion topic with another user (with option to send email invitation to other user) - A page that shows the actual discussion on that Topic. This is the most important page, and here I want 3 tabs, named: Comment, Context, and Confession - The users will be able to do the discussion on the 2 tabs, except on Confession tab. Here I want to retain the ability to first moderate each comment, before making them available to the other user. In nutshell, this should be a simple project requiring some customization of an existing forum-based tool (e.g. Moodle. etc.)!