import Cocoa

class CustomWindow: NSWindowController {

    // This variable will hold our colours
    var windowColor = NSColor(named: "WindowColor") {
        didSet {
            configureWindowAppearance()
        }
    }

    override func windowDidLoad() {
        super.windowDidLoad()

        self.configureWindowAppearance()
    }

    private func configureWindowAppearance() {
        if let window = window {
            if let view = window.contentView {
                view.wantsLayer = true

                window.titlebarAppearsTransparent = true

                // Instead of .white, we use our variable
                window.backgroundColor = windowColor

            }
        }
    }
}