You are looking for a Sublime UI Theme, which modifies Sublime’s User Interface (e.g.: side bar). It’s different from a Color Theme/Scheme, which modifies only the code part of Sublime’s window. I tested a lot of UI Themes and the one I liked the most was Theme – Soda. You can install it using Sublime’s Package Control. To enable it, go to Preferences >> Settings – User and add this line:
"theme": "Soda Dark 3.sublime-theme",
Here is a printscreen of my Sublime Text 3 with Soda Dark UI Theme and Twilight default Color Scheme: