The S5 Accordion menu is demo'd on this page. The styling of the module shown here is customized specifically for this template with css overrides, and cannot be used with any other template. The same module can be used on any template, but with default or other styling in its place.

The accordion can be opened or closed by default on page load. This is configured in the backend configuration.

This module is based off the Joomla main menu system module so you can still specify which Joomla menu you want to use with the S5 Accordion menu. The menu is powered off of the default mootools/jquery calls that are built directly into Joomla to avoid any javascript conflicts.