New version

Drab/Ui/components/MainLayout.razor

@@ -0,0 +1,18 @@
+@inherits LayoutComponentBase
+
+<RadzenLayout>
+    <RadzenBody>
+        <div class="rz-p-0" style="margin: auto; width: 100%; max-width: 1900px !important;">
+            @Body
+        </div>
+    </RadzenBody>
+</RadzenLayout>
+<div id="blazor-error-ui" data-nosnippet>
+    An unhandled error has occurred.
+    <a href="." class="reload">Reload</a>
+    <span class="dismiss">🗙</span>
+</div>
+<RadzenDialog/>
+<RadzenNotification/>
+<RadzenTooltip/>
+<RadzenContextMenu/>

Drab/Ui/components/PdfViewer.razor

@@ -0,0 +1,9 @@
+<object data="@($"/pdf/{Filename}")"
+        style="width: 100%; height: 80vh; border: 1px solid gray"
+        type="application/pdf" width="100%" height="500px">
+</object>
+
+@code {
+    [Parameter]
+    public string Filename { get; set; } = string.Empty;
+}

Drab/Ui/components/Routes.razor

@@ -0,0 +1,12 @@
+@using Microsoft.AspNetCore.Components.Routing
+
+<Router AppAssembly="@typeof(App).Assembly">
+    <Found Context="routeData">
+        <RouteView RouteData="routeData" DefaultLayout="@typeof(MainLayout)"/>
+    </Found>
+    <NotFound>
+        <LayoutView Layout="@typeof(MainLayout)">
+            <p>404 – nie znaleziono strony</p>
+        </LayoutView>
+    </NotFound>
+</Router>