Mat-card CSS class not applied in AngularJS

Hi  

My html is not displaying As i expected  in angular in Mat-card

it is display as simple foramt.it will reflecting it

<mat-card>
<mat-form-field>
  <textarea matInput rows="6" [(ngModel)]="eneteredvalue"></textarea>
  <button mat-button color="primary" (click)="OnAddnepost()">Primary</button>
</mat-form-field>
</mat-card>