diff --git a/csharp.nanorc b/csharp.nanorc
index 893bb37..7242dda 100644
--- a/csharp.nanorc
+++ b/csharp.nanorc
@@ -6,7 +6,7 @@ color brightmagenta  "class +[A-Za-z0-9]+ *((:) +[A-Za-z0-9.]+)?"
 # Annotation
 color magenta   "@[A-Za-z]+"
 
-color brightblue "[A-Za-z_][A-Za-z0-9_]*[[:space:]]*[()]"
+color brightblue "[A-Za-z_][A-Za-z0-9_]*[[:space:]]*[(]{1}[)]{1}"
 color green     "\<(bool|byte|sbyte|char|decimal|double|float|IntPtr|int|uint|long|ulong|object|short|ushort|string|base|this|var|void)\>"
 color cyan  "\<(alias|as|case|catch|checked|default|do|dynamic|else|finally|fixed|for|foreach|goto|if|is|lock|new|null|return|switch|throw|try|unchecked|while)\>"
 color cyan  "\<(abstract|async|class|const|delegate|enum|event|explicit|extern|get|implicit|in|internal|interface|namespace|operator|out|override|params|partial|private|protected|public|readonly|ref|sealed|set|sizeof|stackalloc|static|struct|typeof|unsafe|using|value|virtual|volatile|yield)\>"