JSFiddle - React, Tailwind, and code Playground

HTML

<div data-number="1"></div>
<div data-number="2"></div>
<div data-number="3"></div>

CSS

[data-number]::before {
  content: attr(data-number);
}

  [data-number="1"] { color: red; }
  [data-number="2"] { color: blue; }
  [data-number="3"] { color: green; }