diff --git a/less/mixins/vendor-prefixes.less b/less/mixins/vendor-prefixes.less
index afd3331c3..cc5c15eb6 100644
--- a/less/mixins/vendor-prefixes.less
+++ b/less/mixins/vendor-prefixes.less
@@ -54,7 +54,7 @@
 // Prevent browsers from flickering when using CSS 3D transforms.
 // Default value is `visible`, but can be changed to `hidden`
 
-.backface-visibility(@visibility){
+.backface-visibility(@visibility) {
   -webkit-backface-visibility: @visibility;
      -moz-backface-visibility: @visibility;
           backface-visibility: @visibility;