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
return g_browser_client;
}
void AtomBrowserClient::SetApplicationLocale(const std::string& locale) {
  if (!BrowserThread::IsThreadInitialized(BrowserThread::IO) ||
      !base::PostTaskWithTraits(
          FROM_HERE, {BrowserThread::IO},
          base::BindOnce(&SetApplicationLocaleOnIOThread, locale))) {
    g_io_thread_application_locale.Get() = locale;
  }
  *g_application_locale = locale;
}
AtomBrowserClient::AtomBrowserClient() {
  DCHECK(!g_browser_client);
  g_browser_client = this;
}
AtomBrowserClient::~AtomBrowserClient() {
  DCHECK(g_browser_client);
  g_browser_client = nullptr;
}
content::WebContents* AtomBrowserClient::GetWebContentsFromProcessID(
    int process_id) {
  
  
  if (base::Contains(pending_processes_, process_id))
    return pending_processes_[process_id];
  
  
  return WebContentsPreferences::GetWebContentsFromProcessID(process_id);
}
bool AtomBrowserClient::ShouldForceNewSiteInstance(