Target admin page body via CSS class

Found this, but it really should be in WordPress Core:

// Body class for admin
// http://www.kevinleary.net/customizing-wordpress-admin-css-javascript/
function base_admin_body_class( $classes )
{
    // Current action
    if ( is_admin() && isset($_GET['action']) ) {
        $classes .= 'action-'.$_GET['action'];
    }
    // Current post ID
    if ( is_admin() && isset($_GET['post']) ) {
        $classes .= ' ';
        $classes .= 'post-'.$_GET['post'];
    }
    // New post type & listing page
    if ( isset($_GET['post_type']) ) $post_type = $_GET['post_type'];
    if ( isset($post_type) ) {
        $classes .= ' ';
        $classes .= 'post-type-'.$post_type;
    }
    // Editting a post type
    $post_query = $_GET['post'];
    if ( isset($post_query) ) {
        $current_post_edit = get_post($post_query);
        $current_post_type = $current_post_edit->post_type;
        if ( !empty($current_post_type) ) {
            $classes .= ' ';
            $classes .= 'post-type-'.$current_post_type;
        }
    }
    // Return the $classes array
    return $classes;
}
add_filter('admin_body_class', 'base_admin_body_class');