Design an App Mockup

We are looking for a skilled person for a mission in innovative interactive design. We are currently developing a social platform and eshop for fashion and design with the latest technology such as Bootstrap, AngularJS, NodeJS etc. Goals that we have is responsiveness in design rather than separate design for different devices. You should develop the design more like an app than a web site, ie the site should behave and feel more like an app than older pages. We need someone who is well versed in terms of ease of use, interactive and graphic design, etc. Your focus will be primarily on graphic and interactive design, as well as the psychological aspects that create high response for users. A plus is if you can make CSS templates for the design but it is not a requirement. The page is under construction and if you interested in estimating the time, images can be attached on headpages of current system. We would like to work with the workflow platform named invision for this project but if you prefer any similar, just suggest it for us.