I am contemplating a concept, and I just want to see if it is possible... and if so, how.
The Concept: a "design by decade" setup that will allow anyone visiting my site to choose (probably from a drop down menu at the top) a decade targeted theme. For instance, if they chose "1980's" then the theme would change to one featuring neon colors and maybe some acid washed denim... and if they chose "1940's" the theme would change to something featuring World War II textures and army green/khaki colors.
The Question and more: I have seen other wordpress sites that allow the visitor to toggle the header image/color, or the background image/color... but what I am considering is a complete theme change, not a simple, single image/color switch. Is this possible? Obviously I want a basic default template for all first time visitors to see, so the switch should only affect the particular user selecting their decade... and I'd prefer not to require visitors to have a login/password to enjoy the feature.
Worst case scenario: If I can't have it toggle to a whole separate theme, can I at least have it toggle to a different CSS file? that would at least allow a complete color theme change-up with new texture images.
Looking forward to hearing back, thank you in advance.