changed nav background color on hover

assets/css/custom.css

@@ -9,4 +9,7 @@
 }
 .navbar-dark .navbar-nav .nav-link{
     color:white;
+}
+.navbar-dark .navbar-nav .nav-link:focus, .navbar-dark .navbar-nav .nav-link:hover{
+    background-color:#57cbcc;
 }