Nexus theme slider is not showing up when logged out I gradually found that if I comments the following code in custom. css, it shows up.

Any clue what is wrong here.. Any help is appreciated

I faced the same issue, and realised the issues in custom.js
I commented the following code in custom.css and slider showed up

 /* jQuery('#main-menu &gt; nav &gt; ul').mobileMenu({
    prependTo:'.mobilenavi',
    groupPageText: Drupal.t('Main'),
    topOptionText: Drupal.t('Select a page')
  });*/
Yes, it is because your custom.js is causing conflict with the slider.

You need to use the proper synthax for jQuery. 

As mentioned in Working with JavaScript and jQuery

(function($) {
Drupal.behaviors.myBehavior = {
  attach: function (context, settings) {

    //code starts
    $('#main-menu &gt; nav &gt; ul').mobileMenu({
    prependTo:'.mobilenavi',
    groupPageText: Drupal.t('Main'),
    topOptionText: Drupal.t('Select a page')
    //code ends

  }
};
})(jQuery);