The Extra Theme doesn't come with an option to change the background color of widget titles. Here's how to do it.
About Extra Booster
Extra Booster is a site about the Extra Theme by Elegant Themes. It is a collection of my tips for making the most out of the theme.
The site is partially supported by affiliate links, which may earn me a small commission if you click on them. There is no cost to you and I only link to products I use myself.