JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
  <li data-test="one" data-people='{"name" : "Paul", "color" : "black"}'>Paul</li>
  <li data-test="two" data-people='{"name" : "John", "color7" : "blond"}'>John</li>
  <li data-test="three" data-people='{"name" : "Jane", "color" : "black"}'>Jane</li>
</ul>

CSS

ul li[data-people*='"color" : "blond"'] { color: red }