css connection problem?

Question

htaccess

hello
, when connecting css styles, it displays such a warning
Resource interpreted as Stylesheet but transferred with MIME type application/x-httpd-php
code in the htaccess file:
DirectoryIndex index.php
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php
how to fix this ?