diff --git a/resources/skin.less b/resources/skin.less
index a4b724d..6fbf2a2 100644
--- a/resources/skin.less
+++ b/resources/skin.less
@@ -136,7 +136,7 @@ a.new:active, body a.new:active {
   font-size: 100%;
   white-space: nowrap;
   @media screen and ( max-width: @width-breakpoint-semi-mobile ) {
-    max-width: calc(100vw - 170px);    
+    max-width: ~'calc(100vw - 170px)';    
   }
 }