Remove grunion.css: This will remove the stylesheet used for JetPack's contact form thereby allowing you to write your own styles and not having to resort to using !important all over the place. The code should be placed in your functions.php file.

grunion.php

<?php
//* Do NOT include the opening php tag

//* Remove JetPack's grunion stylesheet used for the contact form
function remove_grunion_style() {
     wp_deregister_style('grunion.css');
}
add_action('wp_print_styles', 'remove_grunion_style');