function add_editor_style( $stylesheet = 'editor-style.css' ) {
	global $editor_styles;

	add_theme_support( 'editor-style' );

	$editor_styles = (array) $editor_styles;
	$stylesheet    = (array) $stylesheet;

	if ( is_rtl() ) {
		$rtl_stylesheet = str_replace( '.css', '-rtl.css', $stylesheet[0] );
		$stylesheet[]   = $rtl_stylesheet;
	}

	$editor_styles = array_merge( $editor_styles, $stylesheet );
}

function get_block_editor_theme_styles() {
	global $editor_styles;

	if ( ! WP_Theme_JSON_Resolver::theme_has_support() ) {
		$styles = array(
			array(
				'css'            => 'body { font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif }',
				'__unstableType' => 'core',
			),
		);
	} else {
		$styles = array();
	}

	if ( $editor_styles && current_theme_supports( 'editor-styles' ) ) {
		foreach ( $editor_styles as $style ) {
			if ( preg_match( '~^(https?:)?//~', $style ) ) {
				$response = wp_remote_get( $style );
				if ( ! is_wp_error( $response ) ) {
					$styles[] = array(
						'css'            => wp_remote_retrieve_body( $response ),
						'__unstableType' => 'theme',
					);
				}
			} else {
				$file = get_theme_file_path( $style );
				if ( is_file( $file ) ) {
					$styles[] = array(
						'css'            => file_get_contents( $file ),
						'baseURL'        => get_theme_file_uri( $style ),
						'__unstableType' => 'theme',
					);
				}
			}
		}
	}

	return $styles;
}

function get_theme_file_path( $file = '' ) {
	$file = ltrim( $file, '/' );

	if ( empty( $file ) ) {
		$path = get_stylesheet_directory();
	} elseif ( file_exists( get_stylesheet_directory() . '/' . $file ) ) {
		$path = get_stylesheet_directory() . '/' . $file;
	} else {
		$path = get_template_directory() . '/' . $file;
	}

	/**
	 * Filters the path to a file in the theme.
	 *
	 * @since 4.7.0
	 *
	 * @param string $path The file path.
	 * @param string $file The requested file to search for.
	 */
	return apply_filters( 'theme_file_path', $path, $file );
}

my_load_skin_gutenberg_css(){
			wp_enqueue_style(
				ハンドル名,
				CSSのURL,
				array( 'wp-edit-blocks' ),
				バージョン
			);
}
add_action( 'enqueue_block_editor_assets', 'my_load_skin_gutenberg_css' );