Hi yourgoal,
You’ll need to use a custom CSS file and Firebug or a similar tool to do what you’re looking for here. Here is an article about how to use custom CSS with Business Directory in a way that doesn’t get overwritten on upgrade of BD: https://businessdirectoryplugin.com/support-forum/faq/how-to-use-custom-styles-with-bd-2-1/
If the CSS part isn’t something you’re feeling comfortable about, my best suggestion to get this handled appropriately would be to hire WPCurve to help you out here—they’re WP experts and for $69, you can’t beat their “unlimited 30 min tasks” in a month. This strikes me as something they would definitely be able to fix quickly and easily. They really get these kinds of issues. Here’s how to contact them: https://wpcurve.com
