diff --git a/phpBB/styles/prosilver/theme/bidi.css b/phpBB/styles/prosilver/theme/bidi.css
index cad84b765c..7bf0cca037 100644
--- a/phpBB/styles/prosilver/theme/bidi.css
+++ b/phpBB/styles/prosilver/theme/bidi.css
@@ -723,6 +723,15 @@ ul.linklist li.small-icon > a, ul.linklist li.breadcrumbs span:first-child > a {
 	float: right;
 }
 
+/* Responsive *CP navigation
+----------------------------------------*/
+@media only screen and (max-width: 900px), only screen and (max-device-width: 900px)
+{
+	.rtl #cp-menu, .rtl #navigation, .rtl #cp-main {
+		float: none;
+	}
+}
+
 /**
 * forms.css
 */