title: How to override css of other components from App
body: <p>I need to make fonts for some of my components bigger when my app is in full screen mode. In my App.jsx I have variable that triggers me adding &quot;fullscreen&quot; class to the root DIV of the whole app. I can go brute force and override it like <code>* { font-szie: 18px; }</code> but thats too simple. I want to override certain classes only (like <code>.some-class * { font-size: 18px; }</code>). Of course React hash stands in my way so here is question: how do I apply my font size to all components in the app?</p>