override func viewWillAppear(_ animated: Bool)
{
    super.viewWillAppear(animated)
    
    NotificationCenter.default.addObserver(self,
                                           selector: #selector(theAppDidBecomeActive),
                                           name    : UIApplication.didBecomeActiveNotification,
                                           object  : nil)
}

override func viewWillDisappear(_ animated: Bool)
{
    super.viewWillDisappear(animated)
    
    NotificationCenter.default.removeObserver(self,
                                      name  : UIApplication.didBecomeActiveNotification,
                                      object: nil)
}

@objc func theAppDidBecomeActive()
{
    // Check Dark Mode in Settings
    if let choice = isDarkModeSettingsChanged()
    {
        changeDarkModeManually(choice)
    }
}

import UIKit
import PerseusDarkMode

public let DARK_MODE_SETTINGS_KEY = "dark_mode_preference"

func changeDarkModeManually(_ userChoice: DarkModeOption)
{
    // Change Dark Mode value in settings bundle
    UserDefaults.standard.setValue(userChoice.rawValue, forKey: DARK_MODE_SETTINGS_KEY)
    
    // Change Dark Mode value in Perseus Dark Mode library
    AppearanceService.DarkModeUserChoice = userChoice
    
    // Update appearance in accoring with changed Dark Mode Style
    AppearanceService.makeUp()
}

func isDarkModeSettingsChanged() -> DarkModeOption?
{
    // Load enum int value from settings
    
    let option = UserDefaults.standard.valueExists(forKey: DARK_MODE_SETTINGS_KEY) ?
        UserDefaults.standard.integer(forKey: DARK_MODE_SETTINGS_KEY) : -1
    
    // Try to cast int value to enum
    
    guard option != -1, let settingsDarkMode = DarkModeOption.init(rawValue: option)
    else { return nil }
    
    // Report change
    
    return settingsDarkMode != AppearanceService.DarkModeUserChoice ? settingsDarkMode : nil
}

// Configure Dark Mode user control

optionsPanel.segmentedControlValueChangedClosure = { option in changeDarkModeManually(option) }
optionsPanel.segmentedControlValue = AppearanceService.DarkModeUserChoice

import UIKit

protocol UICustomColors
{
    static var _customTeal                : UIColor { get }
}

import UIKit
import PerseusDarkMode

extension UIColor: UICustomColors
{
    static var _customTeal                : UIColor
    {
        AppearanceService.shared.Style == .light ? #colorLiteral(red: 0.1882352941, green: 0.6901960784, blue: 0.7803921568, alpha: 1) : #colorLiteral(red: 0.2509803921, green: 0.7843137254, blue: 0.8784313725, alpha: 1)
    }
}

import AdaptedSystemUI

let view = UIView()
view.backgroundColor = .systemRed_Adapted

import AdaptedSystemUI

let view = UIView()
view.backgroundColor = .label_Adapted

import UIKit
import PerseusDarkMode

var topImage = DarkModeImageView()
var bottomImage = DarkModeImageView()

topImage.setUp(UIImage(named: "TheFellowship"), UIImage(named: "FrodoWithTheRing"))
bottomImage.setUp(UIImage(named: "Rivendell"), UIImage(named: "RivendellDark"))