How to include Lumo Styles in a React App?

HI, I am trying to make

It try to make vaadin-grid work in a react app. This works somehow, but I fail to style it properly.
The Dom Inspector in chrome tells me that inside the vaadin-cell-content the lumo vars are undefined.
Any changes I make in the following snippet seem to have no effect.

import {} from '@polymer/polymer/lib/elements/custom-style';
import '@vaadin/vaadin-lumo-styles/all-imports';

declare global {
    namespace JSX {
        interface IntrinsicElements {
            'custom-style': any;

const CustomStyle = () => {

    return (
            <style>{"" +
            "   html {" +
            "                --lumo-font-family: Lato"+
            "            }"


export default CustomStyle;

Are there ideas how to solve this?