In the .jsx where your app is rendered, simply import your ./styles.css

import { createRoot } from 'react-dom/client';
import '../styles.css' 
 
 
function App()
{
    return <>
        <h1> bazinga! </h1>
    </>
}
 
const container = document.getElementById("root");
if (container) {
  const root = createRoot(container);
  root.render(<App/>);
}

todo I do not know why this works or how it works. I also don’t know why, in electron, importing the css within the .html via <link>’s don’t work either (something about MIME)