The entirety of the Material Design are available from Google directly. I will give a brief overview of some of the specification that answers your questions directly. However, I thoroughly recommend you take the time to fully read the documentation if you're designing an application for commercial purposes.
The graphic is given in the Material Design spec. To summarise, layouts under 600dp wide may fill the screen with a single level of content hierarchy. Layouts over 600dp wide may place two levers of content hierarchy on the screen (both summary and detail content).
Layouts over 1600dp wide may let the layout grow until it hits max width. At this point, the grid may do one of the following:
- Become center aligned with increased margins
- Remain left aligned while the right margin grows
- Continue to grow while revealing additional content
Roboto is the standard typefaces on Android, whereas Noto is the standard typeface for all languages on Chrome and is used on Android for languages not covered by Roboto.
App Bar: Title style, Medium 20sp
Buttons: Medium 14sp, all caps
Subheading: Regular 16sp (device), 15sp (desktop)
Body 1: Regular 14sp (device), 13sp (desktop)
Text contrast ratios: Minimum: 4.5:1 | Preferred: 7:1