Navigation menu broken on mobile

Site URL: https://www.lotushealing.fr/home-en

Hello everyone!

My website is broken on mobile and I can't figure out why.

It is about the "Bookings" tab in the navigation menu. It shows up and works on computer, but on mobile, it doesn't.

This tab belongs to an English section of the website

https://www.lotushealing.fr/home-en

This is what I have in Design > Custom CSS

/*HOVER COLOR*/
.header-nav-wrapper a:hover {
color: #78b094 !important;
  transition: width 1s;
}

/*LANGUAGE BUTTON ENG*/
.header-nav-item [href*="home-en"] {
 	font-size: 11px;
    color: white !important;
    background-color: #78b094;
    padding: 0.1rem 0.9rem !important; 	
  border-radius: 0.9rem
}

/*LANGUAGE BUTTON FR*/
.header-nav-item [href*="home"] {
 	font-size: 11px;
    color: white !important;
    background-color: #78b094;
    padding: 0.1rem 0.9rem !important; 	
  border-radius: 0.9rem
}

And what i have in the home-en page

- used to hide the French Language Navigation Links
- used to redirect the homepage button to the right language

<style>
  #header .header-nav-item:nth-child(1) {
  display:none
  }
  #header .header-nav-item:nth-child(2) {
  display:none
  }
  #header .header-nav-item:nth-child(3) {
  display:none
  }
  #header .header-nav-item:nth-child(4) {
  display:none
  }
  #header .header-nav-item:nth-child(5) {
  display:none
  }
</style>
<style>
@media screen and (max-width:1511px) {
    #header .header-menu-nav-item:nth-child(1) {
	display:none
      }
    #header .header-menu-nav-item:nth-child(2) {
	display:none
      }
    #header .header-menu-nav-item:nth-child(3) {
	display:none
      }
    #header .header-menu-nav-item:nth-child(4) {
	display:none
      }
    #header .header-menu-nav-item:nth-child(5) {
  display:none
  }
}
</style>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
$(document).ready(function() {
	$('a#site-title').attr('href','/home-en');
});
</script>

Does anyone know how to fix this?

Love n blessings ❤️

Not related, but have you tried this free guide to add 2 languages, it will be easier.

https://www.bradgood.net/articles/multi-language-content-on-any-squarespace-template