如何使用angular 2在子页面中使用父styleUrl？

@Component({
  selector: 'app-parent',
  templateUrl: './parent.component.html',
  styleUrls: ['./parent.component.css']
})

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

@Component({
  selector: 'app-child',
  templateUrl: './child.component.html',
  styleUrls: ['./child.component.css']
})
export class ChildComponent {
  @Input() parentStyleUrl: string;
}

<app-child [parentStyleUrl]="'./parent.component.css'"></app-child>

<!-- 子组件的模板 -->
<div class="child-component" [ngStyle]="{'background-color': 'red'}">
  子组件的内容
</div>