diff --git a/app/views/layouts/application.html.erb b/app/views/layouts/application.html.erb
index de56a65..b2f2edd 100644
--- a/app/views/layouts/application.html.erb
+++ b/app/views/layouts/application.html.erb
@@ -133,6 +133,10 @@
           box-shadow: inset 0 0 0 2px #0d6efd;
       }
 
+      .day-cell.outside-month {
+          background: #f8f9fa;
+          opacity: 0.6;
+      }
   </style>
 
   <script>