keyboard.component.html

<div class="keyboard-container">
  <div class="character-row">
    <ng-container *ngFor="let upperCharacter of upperCharacters">
      <app-key class="character-key" [character]="upperCharacter"></app-key>
    </ng-container>
  </div>
  <div class="character-row">
    <ng-container *ngFor="let lowerCharacter of lowerCharacters">
      <app-key class="character-key" [character]="lowerCharacter"></app-key>
    </ng-container>
  </div>
</div>