diff --git a/xml2rfc/data/xml2rfc.css b/xml2rfc/data/xml2rfc.css
index 9adbd4a23..6d9858ef0 100644
--- a/xml2rfc/data/xml2rfc.css
+++ b/xml2rfc/data/xml2rfc.css
@@ -136,6 +136,7 @@ svg {
   margin: 1em 0;
 }
 .alignCenter > *:first-child {
+  display: table;
   border: none;
   margin: 0 auto;
 }