Content jumps when Menu appears

Hey there,
great plugin ??
It works fine for me but the issue is that the content seems to jump/shift as soon as the menu slides in.

https://www.ivory-productions.com/ivorynewtest/

I am not sure if I chose the right class? The PHP is seen below and I chose “.navbar” or “.site-header .navbar” or “site-header”

What am I doing wrong??
Please help!
Thanks so much!
Sabina

<header class="site-header">
    <nav class="navbar page-with-cover " role="navigation">
        <div class="wrap">
             <div class="navbar-header">
                 <!-- navbar-brand BEGIN -->
                 <div class="navbar-brand-wpz">

                    <a href="https://www.ivory-productions.com/ivorynewtest/" class="custom-logo-link" rel="home" itemprop="url"><img src="https://i1.wp.com/www.ivory-productions.com/ivorynewtest/wp-content/uploads/2017/02/cropped-Logo_Text-3-1.png?fit=400%2C100" alt="Ivory Productions" width="200" height="50"></a>
                 </div>
                 <!-- navbar-brand END -->
            </div>

            
                <button type="button" class="navbar-toggle">
                    <span class="sr-only">Toggle sidebar & navigation</span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                    <span class="icon-bar"></span>
                </button>

                <div class="navbar-collapse collapse">

                    <ul id="menu-ivory-1" class="nav navbar-nav dropdown sf-menu"><li class="menu-item menu-item-type-post_type menu-item-object-page menu-item-home current-menu-item page_item page-item-5907 current_page_item menu-item-5957"><a href="https://www.ivory-productions.com/ivorynewtest/" data-ps2id-api="true">Home</a></li>
<li class="menu-item menu-item-type-custom menu-item-object-custom current-menu-item current_page_item menu-item-home menu-item-5959"><a href="https://www.ivory-productions.com/ivorynewtest/#section_id-15907" data-ps2id-api="true">Our Work</a></li>
<li class="menu-item menu-item-type-custom menu-item-object-custom current-menu-item current_page_item menu-item-home menu-item-5960"><a href="https://www.ivory-productions.com/ivorynewtest/#wpzoom_instagram_widget-2" data-ps2id-api="true">About Us</a></li>
<li class="menu-item menu-item-type-custom menu-item-object-custom current-menu-item current_page_item menu-item-home menu-item-5906"><a href="https://www.ivory-productions.com/ivorynewtest/#section_id-35969" data-ps2id-api="true">Contact</a></li>
</ul>
                </div><!-- .navbar-collapse -->

            
        </div>
    </nav><!-- .navbar -->
</header><!-- .site-header -->