For those interested this is what I am using:

QLabel {
border-width: 1px;
padding: 1px;
border-style: solid;
border-radius: 5px;
background: qlineargradient(x1:0, y1:0, x2:1, y2:1,
stop:0 white, stop: 0.8 lawngreen, stop:1 black)
}