fix modern logo displaying bug

ot_templating/Resources/Public/assets/Modern/style/custom.css

@@ -141,6 +141,7 @@
     .mega-menu .menu-logo img {
         box-shadow: 2px 2px 3px 2px rgba(0, 0, 0, 0.3);
         border: solid white 3px;
+        background-color: white;
     }
 
     @media (min-width: 1025px) {