#include <QApplication>
#include <QWidget>
#include <QMouseEvent>
#include <QVBoxLayout>
#include <QLabel>
#include <QTimer>

class ClickableWindow : public QWidget
{
public:
    ClickableWindow(QWidget *parent = nullptr) : QWidget(parent)
    {
        // Create a label to show instructions
        QLabel *label = new QLabel("Click anywhere to change background color!");
        label->setAlignment(Qt::AlignCenter);
        
        // Set up layout
        QVBoxLayout *layout = new QVBoxLayout(this);
        layout->addWidget(label);
        
        // Set initial background color
        setStyleSheet("background-color: black;");
        
        // Set window properties
        setWindowTitle("Click to Change Background Color");
        resize(400, 300);
    }

protected:
    void mousePressEvent(QMouseEvent *event) override
    {
        if (event->button() == Qt::LeftButton) {        
            setStyleSheet("background-color: white");
        }

        QTimer::singleShot(200, this, &ClickableWindow::backToBlack);
        
        QWidget::mousePressEvent(event);
    }

    void backToBlack() 
    {
        setStyleSheet("background-color: black");
    }
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    
    ClickableWindow window;
    window.show();
    
    return app.exec();
}