epub.css: add styling for sup and sub.

Closes #9160.

1 files changed, 8 insertions, 0 deletions

diff --git a/data/epub.css b/data/epub.css
index 4ccb3c379..8b2a3844f 100644
--- a/data/epub.css
+++ b/data/epub.css
@@ -33,6 +33,14 @@ a, a:visited {
 img {
   max-width: 100%;
 }
+sup {
+  vertical-align: super;
+  font-size: smaller;
+}
+sub {
+  vertical-align: sub;
+  font-size: smaller;
+}
 h1 {
   margin: 3em 0 0 0;
   font-size: 2em;