diff --git a/xmpp.css b/xmpp.css
index 081e99d9..562fa28c 100644
--- a/xmpp.css
+++ b/xmpp.css
@@ -942,14 +942,16 @@
   }
 
   sub,
-  sup {
+  sup,
+  .super {
     font-size: 75%;
     line-height: 0;
     position: relative;
     vertical-align: baseline;
   }
 
-  sup {
+  sup,
+  .super {
     top: -0.5em;
   }