diff --git a/less/forum/DiscussionPage.less b/less/forum/DiscussionPage.less
index 6b13968b7..5c95be9ae 100644
--- a/less/forum/DiscussionPage.less
+++ b/less/forum/DiscussionPage.less
@@ -80,7 +80,7 @@
     background: @body-bg;
     padding-bottom: 40px;
     border-top: 1px solid @control-bg;
-    .box-shadow(2px 2px 6px -2px @shadow-color);
+    .box-shadow(0 6px 6px @shadow-color);
     .transition(left 0.2s);
 
     .affix & {