Hover color can't be found

I'm using the woocommerce with sensei subscriptions plugin. I've built an online course. When you go to the course the run the mouse over a lesson in the lesson tree it has a white hover color. I want to change this but I've looked everywhere and I can't find this setting. Is there any way to inspect the element to figure out what it's called and/or where the setting is to change it? If not is that something that I have to use custom css for?