Alternate CSS Class for Crosstabs and Buttons in Design Studio 1.6

Hi all,

I'm new to Design Studio so apologies in advance if this is a very basic question.

At the moment I'm building an application where I want the themes to change at the click of a button. I'm doing this by assigning new CSS classes to each component when this button is clicked. However, I'm struggling to change the theme on the crosstabs and buttons as I'm unsure how to assign a new CSS class that is only activated when the button is clicked without overwriting the CSS that is already in place. Is there a way to get around this that I'm not seeing?

Thanks very much in advance!