built ui for default due time

Management.Web/Pages/Index.razor

@@ -55,10 +55,8 @@ protected override void OnInitialized()
       </button>
     </div>
 
-    <div class="row justify-content-center">
-      <div class="col-auto border rounded bg-light p-3">
-        <InitializeYamlFromCanvas />
-      </div>
+    <div class="border rounded bg-dark-subtle p-3 my-3">
+      <InitializeYamlFromCanvas />
     </div>
   }
 }
@@ -75,3 +73,4 @@ protected override void OnInitialized()
   </div>
   <CourseDetails />
 }
+<br>