diff --git a/static/styles/zulip.css b/static/styles/zulip.css
index 3308f7ffdb..474d0d77d6 100644
--- a/static/styles/zulip.css
+++ b/static/styles/zulip.css
@@ -2564,24 +2564,24 @@ button.topic_edit_cancel {
 }
 
 .user-mention {
-    background-color: hsl(0, 0%, 93%);
+    background: hsl(0, 0%, 93%);
     border-radius: 3px;
     padding: 0 0.2em;
     box-shadow: 0px 0px 0px 1px hsl(0, 0%, 80%);
     margin-right: 2px;
     white-space: nowrap;
-    background-image: -moz-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
-    background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0%,hsla(0, 0%, 0%, 0.1)), color-stop(100%,hsla(0, 0%, 0%, 0.0)));
-    background-image: -webkit-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
-    background-image: -o-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
-    background-image: -ms-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
-    background-image: linear-gradient(to bottom, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
+    background: -moz-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
+    background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,hsla(0, 0%, 0%, 0.1)), color-stop(100%,hsla(0, 0%, 0%, 0.0)));
+    background: -webkit-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
+    background: -o-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
+    background: -ms-linear-gradient(top, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
+    background: linear-gradient(to bottom, hsla(0, 0%, 0%, 0.1) 0%, hsla(0, 0%, 0%, 0.0) 100%);
     display: inline-block;
     margin-bottom: 1px;
 }
 
 .user-mention-me {
-    background-color: hsl(112, 88%, 87%);
+    background: hsl(112, 88%, 87%);
 }
 
 .alert-word {