Web/Mobile designer required for an online portal

We are in the process of building an online platform which is supported on web/mobile. The main functionalities of the portal includes: account creation, login, check out, review, ratings etc. Main functionalities will be discussed once the resource is hired. We are looking for someone who can create visually attractive, ellegant and creative designs for our portal. Responsibilities of the designer includes: providing wireframes, visuals, style guide (html/css) and final designs to the developer.