Field search don't show on smartphone

-- url of the page with the problem -- : www.egimotors.it/index.php/services-ricambi-egimotors
-- HikaShop version -- : 3.3
-- Joomla version -- : 3.8.5

Hi all, in my site the filed of search don't display on smartphone.....where is my error?

Thanks in advance
Marco

...i don't undestand why don't display a fields search on the smartphone

www.egimotors.it/index.php/services-ricambi-egimotors


Thank in advance
Marco