如何使 x 轴刻度加粗?
plot_1 = pg.PlotWidget()
plot_1.setBackground('w')
pen = pg.mkPen(color="k", width=3, style=QtCore.Qt.SolidLine)
plot_1 .setTitle("Title", color="k", size="18pt")
plot_1 .plot(xvals, yvals, pen=pen)
styles = {'color': 'r', 'font-size': '12px', 'font-weight': 'bold'}
plot_1 .setLabel('bottom', 'X label', **styles)