RewriteRule (zip|pdf|doc|ppt|exe|dwg)$ /includes/Downloader.php [NC,L]

RewriteCond %{DOCUMENT_ROOT}%{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !(css|jpg|png|gif|tif|js|php|htc|ico|txt)$ [NC]
RewriteRule ^/([A-Za-z0-9./-]+)/?$ /index.php [QSA]