Add your own custom class to Gravity Forms fields. Much easier to do than having the client go into the backend and add a class through the Form Edit screen.

gravity-forms-field-css-class.php

<?php

add_filter( 'gform_field_css_class', 'chronos_add_custom_field_class', 10, 3 );

function chronos_add_custom_field_class( $classes, $field, $form )
{
    $classes .= ' chronos-' . $field->type . '-field';

    return $classes;
}