JSFiddle - React, Tailwind, and code Playground

HTML

<div class="left">x</div>
<div class="middle">x</div>
<div class="right">x</div>

CSS

.left{
    background: red;
    width:180px;
    float:left;}
.right{
    background: orange;
    width:200px;
    float:left;}
.middle{
    background: yellow;
    float:left;
    width: calc(100% - 380px);}