使用双斜杠.htaccess设置404错误

Question

如何在网址中使用双斜杠在 .htaccess 中设置 404错误？问题是我的cur .htaccess 不是空的？

AddType application/x-httpd-php .php .html

ErrorDocument 404 /404.php

<IfModule mod_rewrite.c>
    Options +FollowSymLinks
    RewriteEngine On
    RewriteBase /

    # redirect from index.(php|asp|aspx|html|htm), main.(php|asp|aspx|html|htm), home.(php|asp|aspx|html|htm)
    RewriteRule ^(.*)index\.(php|asp|aspx|html|htm)$ $1 [R=301,L]
    RewriteRule ^(.*)main\.(php|asp|aspx|html|htm)$ $1 [R=301,L]
    RewriteRule ^(.*)home\.(php|asp|aspx|html|htm)$ $1 [R=301,L]
    RewriteRule ^(.*)default\.(php|asp|aspx|html|htm)$ $1 [R=301,L]

    RewriteCond %{HTTP_HOST} ^(www|dev)\.site\.ru$ [NC]
    RewriteRule ^(.*?)((?:index|default|home)\.(?:php|html?))?$ http://site.ru/$1 [R=301,L,NC]
</IfModule>

非常感谢。