title: Angular Material: how to set background-color (without CSS)
body: <p>I'm developing a pure Material Design application using Angular Material framework.</p>
  
  <p>However, I don't understand how to set containers' background colors (e.g. a login form with a blue background).
  I could do it using CSS of course but I wonder if there's a built-in directive / theme option to do this.</p>