The older version is archived in the "old_version" branch. The new design features side tabs (Sidebery) and a new unique look.
Note: The icons in the context menu are not from me! Find out more information about them here.
Paste the styles from the provided css styles into your firefox profile. Further, copy the sidebery styles into the plugins custom css area.
Lookup here if you dont know how to modify your userChrome.css.