    var style: CalendarStyle!

    if currentStyle == .Dark {
      currentStyle = .Light
      title = "Dark"
      style = StyleGenerator.defaultStyle()
    } else {
      title = "Light"
      style = StyleGenerator.darkStyle()
      currentStyle = .Dark
    }
    updateStyle(style)
    navigationItem.rightBarButtonItem!.title = title
    navigationController?.navigationBar.barTintColor = style.header.backgroundColor
    navigationController?.navigationBar.titleTextAttributes = [NSAttributedString.Key.foregroundColor:style.header.swipeLabel.textColor]