JSFiddle - React, Tailwind, and code Playground

HTML

<div id=fixedWidth>
Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed 
</div>

<div id=theRest>
    The rest of the space The rest of the space The rest of the space The rest of the space The rest of the space The rest of the space The rest of the space The rest of the space The 
</div>

<div id=fixedWidth2>
Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed Fixed 
</div>

CSS

#fixedWidth {
  width: 200px;
  float: left;
  background: blue;
}
#fixedWidth2 {
  width: 200px;
  background: red;
  float:right;
}
#theRest {
  background: green;
  margin-right: 210px;
}