Multiple button colors?

Multiple button colors?

I've downloaded a couple of themes with different sets of colors since I want to have the option of having different colored buttons (e.g. red, green, and gray) on the same page. I'm not clear how to apply multiple themes to the same page - I've been using a statement like this to link to the stylesheet for a particular theme:

<

link href = "../Styles/gray_theme/jquery-ui-1.9.2.custom.css " rel ="stylesheet"/> .
 
If I want some buttons to use the gray_theme, some to use the red_theme, and some to use the green_theme, how would I approach that?
 
Thanks,
 
Dave