Add a class with the category slug?

I’m using this with Events Manager plugin and I’m wondering if there is a way to insert the category slug of an event as a class to the a tag? See where I’ve added ‘category-slug’ below. This would allow users to target specific categories with styles since the background color and border color are inline there is nothing unique to select by. Is there any way to do this other than modifying the plugin files?

`<div class=”fc-content”> <span class=”fc-title”>Event info</span></div>‘