Is there css/java script that will allow me to apply an entire theme to a form?  I'm looking to apply this to a selector and therefore swap out themes based on drop-down or radio button selections.  Thus far I'm able to edit individual elements, but not logos or full themes using:

body {background-color: black; text-transform: uppercase;}

body.theme1 {background-color: blue;}

$(document).ready(function{}{
updateTheme();
$('#q1 select').on('change',updateTheme);
});

function updateTheme(){
   $('body').removeClass;
   $('body').addClass($(;#q1 select').val());
}