diff --git a/docs/readthedocs/source/_static/css/custom.css b/docs/readthedocs/source/_static/css/custom.css
index c8a98675..309fdc2f 100644
--- a/docs/readthedocs/source/_static/css/custom.css
+++ b/docs/readthedocs/source/_static/css/custom.css
@@ -101,4 +101,9 @@ footer.bd-footer{
 /* for tables in notebooks generated by pandas dataframe */
 .rendered_html table {
     table-layout: auto !important;
+}
+
+/* for right sidebar word-break */
+#bd-toc-nav ul li {
+    word-break: break-word;
 }
\ No newline at end of file