i tried to hide frontend with htaccess. in frontend and backend all pages works good. but when i tried to login, create or update anything in backend it gaves "bad request (#400) unable to verify your data submission" error. when i disabled htaccess it works again.
i disabled rewrite url in backend but no chance. here is my htaccess
Options -Indexes
RewriteEngine on
<IfModule mod_rewrite.c>
#If the request starts with backend, then pass it through
RewriteCond %{REQUEST_URI} ^backend
RewriteRule ^ - [L,QSA]
RewriteCond %{REQUEST_URI} !/(frontend|backend)/web/(assets|css)/
RewriteCond %{REQUEST_URI} !(\.css|\.js|\.png|\.jpg|\.gif|robots\.txt|\.php)$ [NC]
RewriteCond %{REQUEST_URI} !(public|backend)
RewriteRule .* frontend/web/index.php [L]
</IfModule>