JSFiddle - React, Tailwind, and code Playground

HTML

<div id="sidebar">Testjbjbbjkkbjo</div>

CSS

body, html {
    width: 100%;
    height: 100%;
    background:blue;
    margin:0;
    padding:0;
}
#sidebar {
    position: absolute;
    left: calc(180/2)%;
    bottom: 0;
    background:white;
}