         collectionView.register(ForecastCell.self, forCellWithReuseIdentifier: "forecast")
         self.addSubview(collectionView)
        
+        // add observer to response change theme notification
+        NotificationCenter.default.addObserver(self, selector: #selector(changeTheme), name: NSNotification.Name(rawValue: "ChangeThemeNotification"), object: nil)
+
     }
     
     override func layoutSubviews() {

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "forecast", for: indexPath) as! ForecastCell
        if forecastDays.count > 0 {
             cell.configCell(day: (forecastDays?[indexPath.row+1])!)
        }
       

class ThreeDaysForecastView: UIView {
    
    var collectionView: UICollectionView!
    var darkStyle = false
    
    var forecastDays: [ForecastDay]! = [] {
        didSet {
            collectionView.reloadData()
