JSFiddle - React, Tailwind, and code Playground

HTML

<div id="menu"></div>
<div id="first"></div>
<div id="second"></div>
<div id="three"></div>

CSS

#menu {
    background:red;
    box-shadow:5px black;
    width:100%;
    height:50px;
    position:fixed;
    top:0px;
}
#first {
    width:100%;
background:green;
    height:1000px;
}
#second {
    width:100%;
background:yellow;
    height:1000px;
}
#three {
    width:100%;
background:pink;
    height:1000px;
}