What many dub as "Extropianism" within the realms of the Independent City-state of Extropia could be seen as confusing and a little hard to define, and while the society is one of open co-operation, this article seeks to set down some helpful hints as to what the nation's regions and culture has come to look like.
As stated in Extropia's covenant, the society is one built on retro-futuristic sci-fi, and an art style best defined as raygun gothic. This translates into influence from art deco and streamline moderne (sweeping perspective lines and metallic fascias), as well as futuristic designs (spires and domes).
Edited from Wikipedia:
Raygun Gothic is a catch-all term for a visual style that incorporates various aspects of the Googie, Streamline Moderne and Art Deco architectural styles when applied to retro-futuristic science fiction environments. Academic Lance Olsen has characterised Raygun Gothic as "a tomorrow that never was". The style has also been associated with architectural indulgence, and situated in the context of the golden age of modern design due to its use of features such as "single-support beams, acute angles, brightly colored paneling" as well as "shapes and cutouts showing motion". The term was coined by William Gibson in his story "The Gernsback Continuum". Raygun Gothic's primary influences include the set designs of Kenneth Strickfaden and Fritz Lang.