diff --git a/docs/book/src/custom.css b/docs/book/src/custom.css
index 07af405..463dd27 100644
--- a/docs/book/src/custom.css
+++ b/docs/book/src/custom.css
@@ -74,4 +74,9 @@ li.chapter-item.affix::before {
 
 li.chapter-item.affix a {
     padding-left: 0;
+}
+
+li.chapter-item.affix a.active {
+    border-left: 0 none;
+    margin-left: 0;
 }
\ No newline at end of file