JSFiddle - React, Tailwind, and code Playground

HTML

<div id="one">one</div>
<div id="two">two</div>
<div id="three">three</div>

CSS

div {
    background: #ccc;
}
#two, #three {
    margin-left:20%;
    width:80%;
    height:500px;
}

#one {    
    position:fixed;
    top:0px;
    bottom:0px;
    left:0px;   
    width:20%; 
}