// Title: Add the slug inside the WordPress page main body tag class
// Description: This function will include the slug
// of every page created inside the class section of the body class.
function slug_body_class_for_pages( $classes ) {
	if ( is_singular( 'page' ) ) {
		global $post;
		$classes[] = 'page-' . $post->post_name;
	}
	return $classes;
}
add_filter( 'body_class', 'slug_body_class_for_pages' );