diff --git a/_static/custom_html.css b/_static/custom_html.css
index fcb1f3e..ee1ed5a 100644
--- a/_static/custom_html.css
+++ b/_static/custom_html.css
@@ -55,6 +55,26 @@ a, a.reference, a.footnote-reference {
 	border-bottom: none;
 }
 
+/* Footnotes */
+
+dl.footnote dt {
+	position: relative;
+}
+
+span.fn-backref {
+	position: absolute;
+	background-color: white;
+	z-index: 999;
+	border: 1px solid #999;
+	border-radius: 4px;
+	padding: 2px;
+	top: -3px;
+}
+
+dl.footnote dt:hover span.fn-backref {
+	display: inline;
+}
+
 /* Sidebar */
 
 div.sphinxsidebarwrapper p.caption {