Unable to change height of the handle of QSlider

[Cupidvogel]

I am trying to design a QSlider where I need to vary the height of the slider handle based on certain parameters. This is what I have so far:

QSlider *fScrollbar = new QSlider(this);
fScrollbar->setGeometry(280,5,10,400);
fScrollbar->setMinimum(5);
fScrollbar->setMaximum(50);
fScrollbar->setTracking(true);
fScrollbar->setStyleSheet("QSlider::handle:vertical  { width: 190px; background: black;  }");

QSlider *fScrollbar = new QSlider(this);
fScrollbar->setGeometry(280,5,10,400);
fScrollbar->setMinimum(5);
fScrollbar->setMaximum(50);
fScrollbar->setTracking(true);
fScrollbar->setStyleSheet("QSlider::handle:vertical  { width: 190px; background: black;  }");

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This is not working as expected, the handle still defaults to a small height which is not changing. This is what which is appearing:

slider.jpg

How do I make it work?