I'd like to use a form with post/page content where the content floats around the form. I think this can be done by using a custom class and some CSS, but I may want to use the same form on its own without the post/page content floating, or in a sidebar. Any custom class I add would apply to all instances of the form. Is it possible to add a custom class via a shortcode parameter or some other means? Is there any other way to control when the custom class is applied so that I don't have to have 2 forms for every situation where I want this control?