How can I place PHP anonymous function to execute CSS inside another function in WordPress

I am not a programmer so I’m sure this is a no brainer. I am trying to disable a popup if WordPress users are not logged in. I am using CSS to disable the popup for a specific Woocommerce plugin. The CSS code works fine if I use it by itself. However, when I try to use it with the PHP function to check if users are logged in it does nothing. Any help would be greatly appreciated.

add_action('disable_popup','check_if_logged_in');

function check_if_logged_in()
{
 if (! is_user_logged_in())
      {
          
      add_action( 'wp_head', function () { ?>
    <style>
    .ex-fdlist .exwf-order-method { display: none; }
    </style>
<?php });
 }
}

Answer

Probably you don’t have an action named disable_popup being called. Did you already try something like this?

add_action(
    'wp_head',
    function () {
        if ( ! is_user_logged_in() ) {
            ?>
            <style>
            .ex-fdlist .exwf-order-method { display: none; }
            </style>
            <?php
        }
    }
);