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
#include "shell/browser/atom_paths.h"
#include "shell/browser/atom_quota_permission_context.h"
#include "shell/browser/atom_speech_recognition_manager_delegate.h"
#include "shell/browser/child_web_contents_tracker.h"
#include "shell/browser/font_defaults.h"
#include "shell/browser/io_thread.h"
#include "shell/browser/media/media_capture_devices_dispatcher.h"
#include "shell/browser/native_window.h"
#include "shell/browser/net/network_context_service.h"
#include "shell/browser/net/network_context_service_factory.h"
#include "shell/browser/net/proxying_url_loader_factory.h"
#include "shell/browser/notifications/notification_presenter.h"
#include "shell/browser/notifications/platform_notification_service.h"
#include "shell/browser/session_preferences.h"
#include "shell/browser/ui/devtools_manager_delegate.h"
#include "shell/browser/web_contents_permission_helper.h"
#include "shell/browser/web_contents_preferences.h"
#include "shell/browser/window_list.h"
#include "shell/common/application_info.h"
#include "shell/common/options_switches.h"
#include "shell/common/platform_util.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/resource/resource_bundle.h"
#include "v8/include/v8.h"
#if defined(OS_WIN)
#include "sandbox/win/src/sandbox_policy.h"
#endif
#if defined(USE_NSS_CERTS)
#include "net/ssl/client_cert_store_nss.h"
#elif defined(OS_WIN)