Mobile menu dissapear when clicked

Let’s see the issue

the site is:

https://www.practicasweb.esy.es/wordpress

Apply this style just for mobile:

.navbar .nav {
 max-height: none;
}

Ok, ill try, thank you Andrew!

It worked! thank you very much Andrew ??

So

.navbar.resp .nav{
max-height: none;
}

Hi, I am new to WP. I also have problems with the menu button disappearing after clicking it on mobile devices. I have Customizr theme with a child theme. I tried inserting the code on the style. css in the child theme and in the css section of the theme itself and does not work. where do I insert the code?
Thanks!