Mobile Subpage preview - problem

Site URL: https://www.czechthemountains.com/

Hello,
I would like to ask if anybody can help me with the subpage preview on mobile in the Czech language. 

I have a problem seeing subpages in Stezky, but it works perfectly in the English version. I was told that there is a problem with scripts. I also tried to delete all ccs and scripts on the 2 subpages, but it didn't help.

Any ideas on how I can solve this problem? 

Thank you very much.

This code caused problem

@media screen and (max-width:1511px){#header .header-menu-nav-item:nth-child(1) {display:none}}
  
@media screen and (max-width:1511px){#header .header-menu-nav-item:nth-child(2) {display:none}}

You can check it again