Home .htaccess 403 error without ErrorDocument
 I need to set up error document when 403 error happens. I try to set ErrorDocument 403 403.html in .htaccess, but it doesn't work, because ErrorDocument wants to get full url with / at start. The problem is that I don't know the full path to the document, but it's located in the same folder with .htaccess. All this folder is a project, that user can move anywhere in Apache server without any .htaccess changing. Can I use any Rewrite rules here?