Adding class selectors to html tag with modular css?

Question

React

You need to set two elements

<div className="1">1</div>
<div className="2">2</div>

, from different components

<DivOne/>
<DivTwo/>

changing the width when adding an .active class tag to html, is it possible to do this and how to do it? If the css of both components is connected in a modular way