cornerstone-child_functions.php

<?php

// Enqueue CSS
function load_cornerstone_css() {

	wp_enqueue_style(
		'cornerstone_child_css',
		get_stylesheet_directory_uri() . '/style.css',
		array('foundation_css'),
		false,
		'all'
	);
	wp_enqueue_style(
		'jquery_flipster_css',
		get_stylesheet_directory_uri() . '/vendor_css/jquery.flipster.css',
		array('foundation_css'),
		false,
		'all'
	);
	wp_enqueue_style(
		'flipster_overrides_css',
		get_stylesheet_directory_uri() . '/vendor_css/flipster_overrides.css',
		array('foundation_css'),
		false,
		'all'
	);
}
// don't think you need this line anymore, but uncomment if you do
//add_action( 'wp_enqueue_scripts', 'load_cornerstone_css' );

// Enqueue Scripts
function load_cornerstone_scripts() {
	wp_enqueue_script(
		'jquery_flipster_js',
		get_stylesheet_directory_uri() . '/js/jquery.flipster.js',
		array(),
		'0.3.2',
		true
	);
}
// don't think you need this line anymore, but uncomment if you do
//add_action( 'wp_enqueue_scripts', 'load_cornerstone_scripts' );

// Disable the admin bar on mobiles but enable on desktops
function cornerstone_show_admin_bar() {
	if( wp_is_mobile() || !is_user_logged_in() ) {
		return false;
	} else {
		return true;
	}
}

add_action( 'show_admin_bar' , 'cornerstone_show_admin_bar');

Now I'm getting zero styles delivered to theme, rather than 2 copies of Foundation.