Hello,
This type of feature is mainly of an aesthetic & display type.
The work of the HikaShop team is above all to provide solutions and systems to make your E-commerce work.
Additionally, we think that there are already template or plugins offering this specific effect.
In details, use the "categories on 2 levels" module. Simply activate it via the Joomla module manager.
And besides, it is activated automatically with the default configuration of the installation wizard at the end of the HikaShop installation.
It will be displayed with the same operation, but the look of the module depends on the template (or a display plugin) used. So by default you will have a simple look and if you want the same look as on our demo site, you will have to use either the same CSS or the same Joomla template (or a template offering this effect).
See our Demo website,
here
.
Regards