diff --git a/docs/book.toml b/docs/book.toml
index 0e19be438..7e2fa9820 100644
--- a/docs/book.toml
+++ b/docs/book.toml
@@ -4,3 +4,6 @@ language = "en"
 multilingual = false
 src = "src"
 title = "TaskChampion"
+
+[output.html]
+default-theme = "ayu"