Angular Dart Material Datepicker theming is not working

app_component.dart

import 'package:angular/angular.dart';
import 'package:angular_components/utils/browser/window/module.dart';
import 'package:angular_components/material_datepicker/module.dart';
import 'package:angular_components/material_datepicker/material_date_time_picker.dart';


@Component(
  selector: 'my-app',
  styleUrls: ['app_component.css'],
  templateUrl: 'app_component.html',
  providers: const [
    windowBindings,
    datepickerBindings
  ],
  directives: const [
    MaterialDateTimePickerComponent,
  ]
)
class AppComponent {
}

app_component.html

<h1>Material DateTimePicker</h1>

<h2>Date and Time Picker</h2>
<material-date-time-picker></material-date-time-picker>

app_component.scss

@import 'package:angular_components/css/material/material';
@import 'package:angular_components/material_datepicker/mixins';

:host {
    @include material-calendar-picker-theme($mat-grey-map);
}