comment ajouter des CS en utilisant le niveau indigène en angulaire

import { ..., AfterViewInit, ElementRef, ViewChild, Renderer2, ... } from '@angular/core';
...
export class AdvertisementDirective implements AfterViewInit {

  @ViewChild('templateRefName') el: ElementRef;

  constructor(
    private renderer: Renderer2
  ) {
  }

  ngAfterViewInit() {
    this.renderer.setStyle(this.el.nativeElement, 'background', 'yellow');
    this.renderer.setProperty(this.el.nativeElement, 'innerHTML', '<p>Hello World<p>');
  }

}
Blue-eyed Badger