FixFlow is a "skin" created for PmWiki by Hans Bracker. Maybe "face" would be a better name, since it is what you are facing here: the appearance in form of colours, fonts and borders used, the specific layout of the page and its navigational aids, and the functionality of buttons and links employed therein.
FixFlow can show many different faces, and it is highly customisable and changable in its looks and functions. If Style Options are enabled you can choose from a number of styles for colours, fonts and layouts, for your own use, without affecting others.
FixFlow is under constant development. You can find detailed information on the Pmwiki website at Cookbook:FixFlowSkin or at www.softflow.co.uk/design/
This page may have a more recent version on pmwiki.org: PmWiki:FixFlowSkin, and a talk page: PmWiki:FixFlowSkin-Talk.