Google introduced the Material Design paradigm during its IO 2014 developer event. Since then, they have actively encouraged all android app developers to ensure their apps conform to the Material Design specifications. Google has taken the lead on this, upgrading all their apps with Material specs. With Android Lollipop, material design is baked into the OS.
The Material Design spec is a pretty extensive document and we have gone over this document for you, and picked out some of the more important points.Introduction
The major focus of the material spec is to produce a visual language that provides a unified experience across different platforms and device sizes. [...]