stylesheet.css

/*
 * CSS Spreadsheet is used for widgets that cannot be styled in its layout
*/

QLabel#title {
    font-weight: bold;
}

/* Set minimum size to be 10x the size of the handle */
QSlider:horizontal {
    min-width: 400px;
}

QSlider:vertical {
    min-height: 400px;
}

/* Background of a slider */
QSlider::groove {
        background: white;
        border: 1px solid #424242;
}

/* Handle of a horizontal slider */
QSlider::handle {
        width: 40px;
        border: 1px solid black;
	background-color: #696969;
}

QSlider::handle:horizontal {
    width: 40px;
}

QSlider::handle:vertical {
    height: 40px;
}

/* Area of the groove behind the handle of a slider */
QSlider::sub-page:horizontal, QSlider::add-page:vertical {
    /* Slight white gradient on top */
    background: qradialgradient(cx: 0.5, cy: 0.5, radius: 3, fx: 0.5, fy: 0, stop: 0 dodgerBlue, stop: 1 white);
    border: 1px solid dodgerBlue;
}

/* Area of the groove in front of the handle of a slider */
QSlider::add-page:horizontal, QSlider::sub-page:vertical {
    /* Slight grey shadow on bottom */
    background: qradialgradient(cx: 0.5, cy: 0.5, radius: 5, fx: 0.5, fy: 0, stop: 0 white, stop: 1 #424242);
    border: 2px solid lightgrey;
}

QPushButton {
    background: qradialgradient(cx: 0.5, cy: 0.5, radius: 0.75, fx: 0.5, fy: 0.5, stop: 0 transparent, stop: 1 lightgrey);
    padding: 15px;
    border: 1px solid #a0a0a0;
    border-radius: 25%;
    qproperty-iconSize: 80px;
}
QPushButton:pressed {
    background: qradialgradient(cx: 0.5, cy: 0.5, radius: 1, fx: 0.5, fy: 0.5, stop: 0 transparent, stop: 1 #a0a0a0);
}

QPushButton:disabled {
    background: transparent;
}