Html – Unable to rotate font-awesome icon in Angular 15 with CSS

I’m trying to get a button with an fa-icon to rotate 180degrees and then rotate backwards the other way when it’s clicked again. So far I have this (reproduced in the stackblitz), but the icon just does not rotate at all when the button is clicked. Can this be achieved through CSS or do I need to go about this another way?

Stack Blitz: https://stackblitz.com/edit/angular-ivy-5nbjjw?file=src%2Fapp%2Fapp.component.css

app.component.css

.expandButton:focus i {
  animation: rotate 1s ease-in-out 0s;
}

@keyframes rotate {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

app.component.ts

import { Component, VERSION } from '@angular/core';
import { faChevronDown } from '@fortawesome/free-solid-svg-icons';

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
export class AppComponent {
  faChevronDown = faChevronDown;
}

app.component.html

<button class="expandButton" mat-raised-button color="primary" type="button">
  <i><fa-icon [icon]="faChevronDown"></fa-icon></i>
</button>

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';

import { AppComponent } from './app.component';
import { PhotoGalleryComponent } from './components/photo-gallery/photo-gallery.component';
import {
  FaIconLibrary,
  FontAwesomeModule,
} from '@fortawesome/angular-fontawesome';
import { faChevronDown } from '@fortawesome/free-solid-svg-icons';

@NgModule({
  imports: [
    BrowserModule,
    FormsModule,
    PhotoGalleryComponent,
    FontAwesomeModule,
  ],
  declarations: [AppComponent],
  bootstrap: [AppComponent],
})
export class AppModule {
  constructor(library: FaIconLibrary) {
    library.addIcons(faChevronDown);
  }
}