Disable sidebar with mobile max-device-width

I would like to disable the sidebar in mobile mode from within the php template with max-device-width; something like the below. What would be appropriate code for this?

<?php if (wp_is_mobile() ) and (max-device-width: 720)
	{
	//do nothing
}
	else
	{
	< ? php get_sidebar(); ? >;
}
?>