A ProWiki can look any way you want it to. You can design a HTML / CSS page (with the functional elements of the wiki in mind) and then put the insertion commands into your design. The ProWiki script will combine design and wiki page data dynamically for each request. See WikiRenderingProcess for more detail.
Because of the ideas of WikiIndividuality we have not prepared a fixed set of "skins" for the User to choose from. Instead, we have it made easy to look at the existing ProWikis and their templates, to adapt them marginally (e. g. by just adding your logo) or fundamentally. Let them inspire you. See HowToAdmin/AccessProWikiTemplates for how to do this.