diff --git a/README.md b/README.md
index cd3573e..d838d23 100644
--- a/README.md
+++ b/README.md
@@ -161,7 +161,7 @@ extra = {
     'success': '#17a2b8',
 
     # Font
-    'font-family': 'Roboto',
+    'font_family': 'Roboto',
 }
 
 apply_stylesheet(app, 'light_cyan.xml', invert_secondary=True, extra=extra)