Changed color for warning alert

src/css/less/variables.dark.less

@@ -257,7 +257,7 @@
 // Form states and alerts
 // -------------------------
 @warningText:             darken(#c09853, 10%);
-@warningBackground:       @grayLighter;
+@warningBackground:       @orange;
 @warningBorder:           transparent;
 
 @errorText:               #b94a48;