I've been waiting for an add-on like this! Rated 5 out of 5 stars
I've been waiting for this functionality in Firefox for a very long time. I'm also very glad that it also works for pinned tabs, as I have Facebook and GMail both pinned. My only suggestion would be to allow for more refined customization of the colors using hex codes.This review is for a previous version of the add-on (1.10.1-signed).