QWidgetDemo/third/qwtdemo/examples/stylesheets/choco.css

QwtPlot
{
    border: 1px solid white;
    border-radius: 10px;
    padding: 10px;
    background-color: qlineargradient( x1: 0, y1: 0, x2: 0, y2: 1,
        stop: 0 Brown, stop: 0.5 Chocolate, stop: 1 Brown );
}

QwtPlotCanvas
{
    border: 1px solid White;
    border-radius: 10px;
    background-color: Tan;
}

QwtPlotGLCanvas
{
    border: 1px solid White;
    background-color: Tan;
}

QwtScaleWidget
{
    color: white;
}

QwtTextLabel#QwtPlotTitle
{
    color: white;
}

QwtTextLabel#QwtPlotFooter
{
    color: white;
}

QwtLegend
{
    border: 1px solid white;
    border-radius: 10px;
    padding: 2px;
    background: brown;
}

QwtLegendLabel
{
    color: white;
}