diff --git a/themes/hugo-book b/themes/hugo-book
index 81a841c..4018d4b 160000
--- a/themes/hugo-book
+++ b/themes/hugo-book
@@ -1 +1 @@
-Subproject commit 81a841c92d62f2ed8d9134b0b18623b8b2471661
+Subproject commit 4018d4b51d10427bc7f80da0b0d535a4b4787ba0