Hide element class name on webview React Native

WebViewCustomCss.js

import React, {useEffect} from 'react';
import { WebView } from 'react-native-webview';

export default function OrderReviewScreen() {
    const runFirst = `
      document.getElementsByClassName('main-header')[0].style.display = 'none';
      true; // note: this is required, or you'll sometimes get silent failures
    `;
    return (
        <>
            
            <WebView 
                  source={{ uri: `https://example.cl/`}} 
                  injectedJavaScript={runFirst}
                  style={{backgroundColor: 'blue'}}
           />
        </>
    );
}