[editor] Improve styling

projects/editor/src/app/components/unit-view/page-view/properties/element-properties.component.css

@@ -54,3 +54,8 @@
 .text-text {
   background-color: rgba(0,0,0,.04);
 }
+
+::ng-deep app-element-properties p {
+  text-align: center;
+  font-weight: bold;
+}

projects/editor/src/app/components/unit-view/page-view/properties/element-properties.component.html

@@ -234,5 +234,5 @@
   </mat-tab-group>
 </ng-container>
 <ng-container *ngIf="selectedElements.length === 0">
-  Kein Element ausgewählt
+  <p>Kein Element ausgewählt</p>
 </ng-container>