How can I make button slider have a transparent background?

[Prettybird]

 I would like to be able to make the background behind the circled text transparent but I am unable to find where that can be done. I am using a custom theme "mojuri" . Any help would be greatly appreciated!

[migreen06]

There are 2 ways. Let's start with the easier method. Do you have the "custom  CSS" box? Usually you can find it in the right side panel. Click the button you want to change the background for and in the right side menu scroll all the way to the bottom.