A Theme is used to change the way the browser looks. It modifies the appearance around the border of the browser and as the background when you open a new tab. There are all types of Themes available ranging from Space Themes to Kitty Themes. My site houses many of my own original Themes and a collection of the best Themes available today. Check out all of the Themes on this site here. Also, you can personally Request A Theme from me if you're unable to find what you are looking for.