correct icon color for answered question

src/app/components/shared/comment/comment.component.html

@@ -26,7 +26,7 @@
 
       <button mat-icon-button *ngIf="comment.answer" (click)="openAnswerTextDialog()"
               tabindex="0">
-        <mat-icon matTooltip="{{ 'comment-page.has-answer' | translate }}">comment
+        <mat-icon class="answered-icon" matTooltip="{{ 'comment-page.has-answer' | translate }}">comment
         </mat-icon>
       </button>
 

src/app/components/shared/comment/comment.component.scss

@@ -30,6 +30,10 @@ mat-card-content > :first-child {
   color: slategray;
 }
 
+.answered-icon {
+  color: var(on-surface);
+}
+
 .correct-icon {
   color: var(--green);
 }