This is a theme for CM11 & AOKP, its purpose is to enhance the Android UI without compromising the vanilla look.
For a full black experience get the Dark inverted version.
Stock battery is available as "circle" in settings for AOKP/Liquid.
HOW TO APPLY:
Install the app, go to settings/themes of your ROM, select system theme and REBOOT. After that apply this theme and reboot again.
If you get: "Sorry, this theme is missing assets for your device's screen size", APPLY IT ANYWAY.