角度材质选项卡将图像添加到按钮

Question

我是Angular的初学者。我尝试用Angular材料选项卡做一些事情。我将标签部分添加到图像，但该部分无效。有谁知道如何将图像添加到角度材料选项卡。请查看我的附图，了解我尝试实现的目标。

My code so far (stackblitz demo)

我的代码部分：

<mat-tab-group mat-stretch-tabs class="example-stretched-tabs mat-elevation-z4">
  <mat-tab label="First"  style="background:url('/assets/img/school-01.png')"> Content 1 </mat-tab>
  <mat-tab label="Second"> Content 2 </mat-tab>
  <mat-tab label="Third"> Content 3 </mat-tab>
</mat-tab-group>

CSS

.example-stretched-tabs {
  max-width: 800px;
}
/* active tab */
.mat-tab-list .mat-tab-labels .mat-tab-label-active {
  color:#0f2241;
  background-color: #535353;
  opacity: 1;
}

/* ink bar */
.mat-tab-group.mat-primary .mat-ink-bar {
  background: none;
  content: url('https://image.flaticon.com/icons/svg/60/60995.svg');
  height: 10px; 
}

.TS

import {Component, ViewEncapsulation} from '@angular/core';

/**
 * @title Tab group with stretched labels
 */
@Component({
  selector: 'tab-group-stretched-example',
  templateUrl: 'tab-group-stretched-example.html',
  styleUrls: ['tab-group-stretched-example.css'],
  encapsulation: ViewEncapsulation.None
})
export class TabGroupStretchedExample {}