diff --git a/simple.css b/simple.css
index ef12bbe..6627d35 100644
--- a/simple.css
+++ b/simple.css
@@ -654,6 +654,9 @@ dialog::backdrop {
 sup, sub {
   vertical-align: baseline;
   position: relative;
+}
+
+sup {
   top: -0.4em;
 }