no "congratulations" for local file upload?

re: http://jigsaw.w3.org/css-validator/
 
If I provide the URI of my stylesheet, e.g. http://somewhere.com/xxx.css, it says "Congratulations ...." and lists a few "Warnings"
 
If I upload the SAME xxx.css file from my local drive, it doesn't say "Congratulations ..." - it just lists the same few "Warnings"
 
Why "Congratulations" only from http:// and not from local upload? (for same xxx.css?)
 
John