title: Changing Background Color of Modal for angular_components
body: <p>How do you customize the background color of the ModalComponent in angular_components for dart?</p>
  
  <p>Question pulled from here: <a href="https://github.com/dart-lang/angular_components/issues/187" rel="nofollow noreferrer">https://github.com/dart-lang/angular_components/issues/187</a></p>