TwelF is a Material Design inspired theme for Android Lollipop aiming to provide a unified and minimalistic look to your device. Your ROM must include CM12 Theme Engine. If you are using CM11, you can try Onze Theme.
Market link: https://f-droid.org/repository/browse/?fdid=org.twelf.cmtheme
Web site: https://gitlab.com/xphnx/twelf_cm12_theme
Source code: https://gitlab.com/xphnx/twelf_cm12_theme/tree/master
Code license: GPLv3