How to activate darkmode for the text changed in WkWebViewRenderer?

I was trying to resize the text in a webView in Xamarin.iOS with a webView-renderer. It works, but my problem is that the dark mode does not work anymore. I have already changed the background of the web view, so it is shown right, but I don't know how to do it with the text.

  public class NavigationDelegat : WKNavigationDelegate
{
    public override void DidFinishNavigation(WKWebView webView, WKNavigation navigation)
    {
        string Size = "300%"; 
        string text = String.Format(@"document.getElementsByTagName('body')[0].style.webkitTextSizeAdjust= '{0}'", Size);
        
        WKJavascriptEvaluationResult handler = (NSObject result, NSError err) => {
            if (err != null)
            {
                System.Console.WriteLine(err);
            }
            if (result != null)
            {
                System.Console.WriteLine(result);
            }
        };

        webView.EvaluateJavaScript(text, handler);
        webView.Opaque = false;
        webView.BackgroundColor = UIColor.Clear;


    }
}

How to do it? The text is always black, also when darkMode is activated.

Read more here: https://stackoverflow.com/questions/66320105/how-to-activate-darkmode-for-the-text-changed-in-wkwebviewrenderer