how to change backgroup color, button color and shape?

[AD]

Hello!
I don't find this parts of code but i can to prompt how to change style(for example background-color of buttons)!

QString color = Qt::red;
QString style = "* { background-color: ";
style += color;
style += " }";
QButton btnColor = new QButton(this);
btnColor -> setStyleSheet(style);

QString color = Qt::red;
QString style = "* { background-color: ";
style += color;
style += " }";
QButton btnColor = new QButton(this);
btnColor -> setStyleSheet(style);

To copy to clipboard, switch view to plain text mode 

This method is used for changing other styles so as

P.S. Sorry by my bad english! I'll be one's utmost to learn english better!