Safari Technology Preview now supports dark mode via `@media (prefers-color-scheme: dark)` in CSS media queries. 

Same should be supported in Electron apps to enable automatic light/dark mode switching.

shell/browser/atom_browser_client.cc
content::BrowserContext* browser_context,
    bool ,
    const base::FilePath& ) {
  if (!browser_context)
    return nullptr;
  if (base::FeatureList::IsEnabled(network::features::kNetworkService)) {
    return NetworkContextServiceFactory::GetForContext(browser_context)
        ->CreateNetworkContext();
  } else {
    return static_cast<AtomBrowserContext*>(browser_context)
        ->GetNetworkContext();
  }
}
network::mojom::NetworkContext* AtomBrowserClient::GetSystemNetworkContext() {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);
  DCHECK(g_browser_process->system_network_context_manager());
  return g_browser_process->system_network_context_manager()->GetContext();
}
base::Optional<service_manager::Manifest>
AtomBrowserClient::GetServiceManifestOverlay(base::StringPiece name) {
  if (name == content::mojom::kBrowserServiceName)
    return GetElectronContentBrowserOverlayManifest();
  return base::nullopt;
}
std::vector<service_manager::Manifest>