Google’s Design Guidelines, Assets and Resources
At Google they say, â€œFocus on the user and all else will follow.â€ They embrace that principle in their design by seeking to build experiences that surprise and enlighten their users in equal measure.
Google always challenged themselves to create a visual language for their users that synthesizes the classic principles of good design with the innovation and possibility of technology and science. Google Design spec is a living document that will be updated as they continue to develop the tenets and specifics of material design. You can read their design guidelines, download assets and resources.