The concept of themes in Vue Material have four pillars: Dynamic, Multiple, Flexible and Friendly.
As Vue Material can have dark themes too, the background color of most elements are applied automatically.
Every component can also work with two color intentions, that will change the background and foreground colors: Primary and Accent. Some components also have a Transparent variant to make your layouts cleaner and easier to place on top of other elements. E.g. Tabs inside toolbars.
Color in Material Design is inspired by bold hues juxtaposed with muted environments, deep shadows and bright highlights. The Material Design palette can be fully applied here and you should use the name and the hue number to create themes.
Vue Material use classes to apply those color intentions:
md-transparent. The background color is applied automatically by the theme engine.