From angular styles documentation.
Style URLs in metadata
You can load styles from external CSS files by adding a styleUrls
attribute into a component's @Component decorator:
@Component({
selector: 'hero-details',
template: `
<h2>{{hero.name}}</h2>
<hero-team [hero]=hero></hero-team>
<ng-content></ng-content>
`,
styleUrls: ['app/hero-details.component.css']
})
export class HeroDetailsComponent {
/* . . . */
}
The URL is relative to the application root, which is usually the location of the index.html web page that hosts the application. The
style file URL is not relative to the component file. That's why the
example URL begins src/app/. To specify a URL relative to the
component file, see Appendix 2.
You can also embed tags into the component's HTML template.
As with styleUrls, the link tag's href URL is relative to the
application root, not the component file.
@Component({
selector: 'hero-team',
template: `
<link rel="stylesheet" href="app/hero-team.component.css">
<h3>Team</h3>
<ul>
<li *ngFor="let member of hero.team">
{{member}}
</li>
</ul>`
})
CSS @imports
You can also import CSS files into the CSS files using the standard
CSS @import rule. For details, see @import on the MDN site.
In this case, the URL is relative to the CSS file into which you're
importing.
@import 'hero-details-box.css';
Now. For one of your purposes you could need to change encapsulation. It is the topic here. Load external css style into Angular 2 Component Give a look. It solves you for adding an external CDN but I wanted to give full info and why is it needed. To ensure you it is the only that solves your scenario.
Also, other suggestions there up resolves you for adding script tag. I suggest just add it to your component template, as you should do directly in the html what is yet specific of your component.