JSFiddle - React, Tailwind, and code Playground

HTML

<div class="foo">
  <bar class="bar" >bar</bar>
  <bar  class="bar">bar</bar>
  <bar  class="bar">bar</bar>
  <span>span</span>
</div>

</div>
<div class="foo">
  <bar  class="bar">bar</bar>
  <bar  class="bar">bar</bar>
  <bar  class="bar">bar</bar>
  <baz>baz</baz>
</div>

CSS

.foo > bar.bar:last-of-type{
  background-color: red !important ;
}