Make sidenav fill screen for small displays

src/app/app.component.css

@@ -110,6 +110,10 @@ article {
   .hidemenu {
     visibility: hidden;
   }
+  .sidenav {
+    width: 100%;
+    height: 100%;
+  }
   .topnav h1 {
     padding: 0 0 0 64px;
   }