When printing invoice to screen (browser) invoice is formatted properly using attached css.
when exporting to pdf it looks plain like pdf dont use this css style file.
Also when printing to excel/word system require local css in C:\Users\User\AppData\Local.
How to solve this little issue?
I can not help you with the excel problem. Please open a ticket about it here:
http://code.google.com/p/simpleinvoices/issues/list
Regarding the PDF. Could it be that you try to set some positioning? The PDF library which is doing the transformation from html to pdf can not understand all css commands. So it could be that you use some commands not understood.
Else look in the log file from the webserver if you have some error messages there about local connections.