Add linear gradient to ionic card component

Ionic Framework ionic-v3
1

How can i added linear gradient to this ion card.if i added it in scss file only the background image will be shown.

<ion-card background-size (click)="openSubGallery(img.title,img.item)" [ngStyle]="{'background-image': 'url(' + img.image + ')'}">

                   <ion-card-content>
                        <h2 gallery-title text-wrap>{{img.title}}</h2>
                    </ion-card-content>
                </ion-card>