[on_and_off]

It is a design language from Google. It takes a lot of inspiration from flat design but uses elevation (for example with elevated buttons). the idea is that our minds are used to '3D scan' what is in front of us and that it helps identify clickable elements. Color is also used a lot. In an app, the same accent color is used in order to denote clickable elements.

It gives us a framework with mostly good choices (nothing is perfect) in order to build apps (or websites) that users can use more easily since they will gradually get used to its conventions.