JSFiddle - React, Tailwind, and code Playground

HTML

<div id="top">
  <div id="potato"></div>
</div>
<div id="bottom">
  <div id="potato"></div>
</div>

CSS

div {
  width: 100%;
  height: 50px;
  background-color: #555;
  border: 1px solid black;
}

#potato {
  width: 200px;
}

.Red {
  background-color: red;
}
.Russet {
  background-color: #80461B;
}

JavaScript

$('#top #potato').addClass('Russet');
$('#bottom #potato').addClass('Red');

//$('#top > #potato').addClass('Russet');
//$('#bottom > #potato').addClass('Red');

//  $('#potato').html('Idaho');