JSFiddle - React, Tailwind, and code Playground

HTML

<div>
   <label>
       <input type="radio"/>
       <span>Foo</span>
    </label>
</div>
<div>
   <label>
       <input type="radio"/>
       <span>Bah</span>
    </label>
</div>

CSS

:checked + span {
  font-weight: bold;
}