JSFiddle - React, Tailwind, and code Playground

HTML

<div id="fixedBox">Меню</div>
<br />
                <script>
                    for (i=1; i<101; i++) document.write('<br />');
                </script>

CSS

body {
    min-height:1600px;
}

#fixedBox{
    width:100%;
    background-color:green;
    position:absolute;
    top:120px;
    height:100px;
}

JavaScript

$(function() {
        
        $( document ).scroll( (function() {
            var doc = $( document );
            var div = $( '#fixedBox' );
            var maxOffset = div.offset().top;

            return function() {
                var docScrollTop = doc.scrollTop();
                
                if ( docScrollTop > maxOffset ) {
                    div.css({ top: docScrollTop });
                }

            }
        }()));
        
});