fixing z-orders to hide the top navbar from stage, chord and main view

src/app/app.component.scss

@@ -1,3 +1,10 @@
+// To allow the inner overlay (and other items) to use z-indexes greater than 1
+.mat-sidenav {
+  &-container, &-content {
+    z-index: auto;
+  }
+}
+
 mat-toolbar {
   position: -webkit-sticky;
   position: sticky;

src/app/components/overlay.scss

@@ -5,7 +5,7 @@
   position: fixed;
   left: 0;
   top: 0;
-  z-index: 1;
+  z-index: 1200;
   overflow: hidden;
   color: white;
   display: flex;