JSFiddle - React, Tailwind, and code Playground

HTML

<div class='fixed'>fixed</div>
<div class='wrap'>

<div class='abs'>absolute</div></div>

CSS

html,body{
    margin:0;
}
.fixed{
    width:200px;
    height:90%;
    position:fixed;
    left:0;
    top:0;
    background:#ccc;
    z-index:20;
}
.wrap{
    position:relative;
    width:250px;
    height:1000px;
    background:#ff0;
}
.abs{
    position:absolute;
    width:300px;
    height:200px;
    bottom:0;
    background:#00f;
}