diff --git a/summary/00_header.html b/summary/00_header.html
index 099a15a..763231a 100644
--- a/summary/00_header.html
+++ b/summary/00_header.html
@@ -38,6 +38,15 @@
tr.selected {
background-color: #d1eaff !important;
}
+
+ th.asc::after {
+ content: " 🔼";
+ }
+
+ th.desc::after {
+ content: " 🔽";
+ }
+