diff --git a/themes/hugo-book b/themes/hugo-book
index 3f1bccc..7c78a39 160000
--- a/themes/hugo-book
+++ b/themes/hugo-book
@@ -1 +1 @@
-Subproject commit 3f1bcccbfb247da44ab5410a97576c0bf6da103b
+Subproject commit 7c78a39c531aa2492ed7e92f2ce9dfb2c8c0d3fa