slider and menu overlap

Hi all, i just put the responsive slider on home page, but it’s overlap by menu header.

i found a website which can make it happen.but i don’t know where to modify,anyone know how to fix position under header menu??please advice, thank you!!

here’s the effect what i want.
http://www.ktcdigital.com/veritrak/

by the way: im using juridica theme

https://ww.wp.xz.cn/themes/juridica/