JSFiddle - React, Tailwind, and code Playground

HTML

<div class="menu">Menu</div>

CSS

html{
    height: 1000px;
    background-color: blue;
}

.menu{
    height: 50px;
    width: 100%;
    position: fixed;
    top: 0;
    background-color: red;
}

JavaScript

$(document).ready(function(){
    $(window).scroll(function(){
        if($(window).scrollTop() > $(window).height()){
            $(".menu").css({"background-color":"transparent"});   
        }
    })
})