[ Genesis ] Create body class based on permalink slug

functions.php

//* Add a body class to single pages based on slug
add_filter( 'body_class', 'wc_body_class_for_pages' );
function wc_body_class_for_pages( $classes ) {

	if ( is_singular( 'page' ) ) {
		global $post;
		$classes[] = 'page-' . $post->post_name;
	}

	return $classes;
}