Get Elementor custom css

functions.php

<?php 
add_action( 'graphql_register_types', function() {
           register_graphql_field( 'Page', 'customCSS', [
              'type' => 'String',
              'description' => __( 'Custom CSS from Editor', 'wp-graphql' ),
              'resolve' => function() {
             // call your function which return your custom css
             return $this->addPageCustomCssToGraphql();
              }
           ] );
           } );
?>