Not able to edit Appearance – Not loading

I was tweaking some code in the functions.php and crashed my site. I was able to upload a saved copy of the functions.php.

The does come back up, but the site is missing the store and navigation.

https://www.txprecision.net

When I try to click on Appearance and select Customize I get a HTTP 500 Error.

I checked the error log and see this:
[20-Jun-2016 17:08:34 UTC] PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘storefront_secondary_navigation’ not found or invalid function name in /home2/txprecis/public_html/wp-includes/plugin.php on line 525

I checked that line and it says:
call_user_func_array($the_[‘function’], array_slice($args, 0, (int) $the_[‘accepted_args’]));

Any ideas what I’ve done or how I can fix it?