How to enqueue a theme style-sheet to my admin settings page?

Question

I have a situation in which I am building a plugin that is intentionnally fit for a particular theme. Within my theme I have the following folder structure leading to my css file.

wp-content -> themes -> my-theme-name -> css -> my-custom-css.css

from my plugin, how can I enqueue that template css file onto a specific settings page (FYI - I am currently using the settings API to built my settings page?).

I'm finding tutorials online on how to associate a plugin's style-sheet to the admin area, and that's cool. But I need my theme's custom css file to be enqueued to my custom settings page instead.

Here is something I found in the codex...

Can I do this for a particular settings page?

function wpdocs_enqueue_custom_admin_style() {
        wp_register_style( 'custom_wp_admin_css', get_template_directory_uri() . '/admin-style.css', false, '1.0.0' );
        wp_enqueue_style( 'custom_wp_admin_css' );
}
add_action( 'admin_enqueue_scripts', 'wpdocs_enqueue_custom_admin_style' );

Answer 1

The admin_enqueue_scripts hook has a $hook_suffix parameter for the current admin page. This parameter will return something like toplevel_page_yourpagename where the toplevel_page will be your page level and yourpagename is what you find on the ?page=yourpagename url.

Use that to check if the current page is your plugin's settings page and then load the scripts.

function wpdocs_enqueue_custom_admin_style($hook_suffix) {
    // Check if it's the ?page=yourpagename. If not, just empty return before executing the folowing scripts. 
    if($hook_suffix != 'toplevel_page_yourpagename') {
        return;
    }

    // Load your css.
    wp_register_style( 'custom_wp_admin_css', get_template_directory_uri() . '/admin-style.css', false, '1.0.0' );
    wp_enqueue_style( 'custom_wp_admin_css' );
}
add_action( 'admin_enqueue_scripts', 'wpdocs_enqueue_custom_admin_style' );

Check this for reference https://codex.wordpress.org/Plugin_API/Action_Reference/admin_enqueue_scripts#Example:_Load_CSS_File_from_a_plugin_on_specific_Admin_Page