diff --git a/doc/syntax/autoconf.nanorc b/doc/syntax/autoconf.nanorc
index b578abef..918de3dc 100644
--- a/doc/syntax/autoconf.nanorc
+++ b/doc/syntax/autoconf.nanorc
@@ -20,7 +20,7 @@ color red "\"[^"]*\""  "\'[^']*\'"
 color green "`[^`]*`"
 
 # Error lines:
-color black "^\*\*\*.*"
+color brightred "^\*\*\*.*"
 
 # Brackets:
 color magenta "\[|\]|\(|\)"