diff --git a/static/styles/zulip.scss b/static/styles/zulip.scss
index ce629a190a..ddae91c62e 100644
--- a/static/styles/zulip.scss
+++ b/static/styles/zulip.scss
@@ -993,23 +993,25 @@ td.pointer {
     }
 }
 
-.message_header_private_message .message_label_clickable {
-    background-color: hsl(0, 0%, 27%);
-    display: inline-block;
-    padding: 3px 6px 2px 6px;
-    font-weight: normal;
-    font-size: 14px;
-    height: 17px;
-    line-height: 17px;
-    border-left-color: hsl(0, 0%, 27%);
-}
+.message_header_private_message {
+    .message_label_clickable {
+        background-color: hsl(0, 0%, 27%);
+        display: inline-block;
+        padding: 3px 6px 2px 6px;
+        font-weight: normal;
+        font-size: 14px;
+        height: 17px;
+        line-height: 17px;
+        border-left-color: hsl(0, 0%, 27%);
+    }
 
-/* Base color backgrounds for messageboxes,
-   private messages, mentions, and unread messages */
+    /* Base color backgrounds for messageboxes,
+       private messages, mentions, and unread messages */
 
-.message_header_private_message .message-header-contents {
-    background-color: hsla(192, 19%, 75%, 0.2);
-    box-shadow: inset 1px 1px 0px hsl(0, 0%, 88%);
+    .message-header-contents {
+        background-color: hsla(192, 19%, 75%, 0.2);
+        box-shadow: inset 1px 1px 0px hsl(0, 0%, 88%);
+    }
 }
 
 .private-message .messagebox,