RewriteEngine on

#RewriteCond %{SERVER_PORT} 80
#RewriteRule ^(.*)$ http://www.site_adi.com/$1 [R,L]

#RewriteCond %{HTTP_HOST} ^site_adi.com. [NC]
#RewriteRule ^(.*)$ http://www.site_adi.com/$1 [L,R=301,NC]

çalışma mantıgı
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.*)$ $1.php

RewriteRule ^sayfa-([0-9a-zA-Z-_]+) menu-detay.php?sef=$1 [L,QSA]