Updated UI with BitBlazor components.

JSMR.UI.Blazor/App.razor

@@ -1,4 +1,8 @@
-<Router AppAssembly="@typeof(App).Assembly">
+<HeadContent>
+    <RadzenTheme Theme="material-dark" />
+</HeadContent>
+
+<Router AppAssembly="@typeof(App).Assembly">
     <Found Context="routeData">
         <RouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)" />
         <FocusOnNavigate RouteData="@routeData" Selector="h1" />
@@ -9,4 +13,4 @@
             <p role="alert">Sorry, there's nothing at this address.</p>
         </LayoutView>
     </NotFound>
-</Router>
+</Router>