diff --git a/book.toml b/book.toml
index 6f1daae..0b5c7d0 100644
--- a/book.toml
+++ b/book.toml
@@ -8,4 +8,4 @@ language = "en"
 
 [output.html]
 git-repository-url = "https://github.com/TelegramBots/book"
-additional-css = ["custom.css"]
+additional-css = ["theme/custom.css"]