feat(demo): fixed navigation

Author: tomastrajan

projects/elements-demo/src/app/core/layout/navigation/navigation.component.html

@@ -1,3 +1,4 @@
+<div class="spacer"></div>
 <mat-nav-list>
   <ng-container *ngFor="let nav of navigation">
     <a

projects/elements-demo/src/app/core/layout/navigation/navigation.component.scss

@@ -1,5 +1,15 @@
+:host {
+  position: relative;
+}
+
+.spacer {
+  min-width: 250px;
+}
+
 mat-nav-list {
   padding-top: 0;
+  position: fixed;
+  top: 64px;
 }
 
 a[mat-list-item] {
@@ -18,3 +28,9 @@ a[mat-list-item] {
     margin: 0 0 0 30px;
   }
 }
+
+:host-context(.responsive) {
+  mat-nav-list {
+    top: 56px;
+  }
+}