@mrjj Thank you very much! I have researched and been able to do what I was looking for. Here's what I did:

def drawPrimitive(self, element, opt, painter, widget): if element == QStyle.PE_PanelButtonTool: pressed = (opt.state & STATE_SUNKEN | opt.state & STATE_ON) color = QColor("#323232") if pressed: color = QColor("#222222") elif opt.state & STATE_ENABLED and opt.state & STATE_MOUSEOVER: color = QColor("#4e4e4e") painter.fillRect(opt.rect, color) elif element == QStyle.PE_IndicatorArrowDown or \ element == QStyle.PE_IndicatorArrowUp: r = opt.rect size = min(r.height(), r.width()) image = QImage(size, size, QImage.Format_ARGB32_Premultiplied) image.fill(Qt.transparent) image_painter = QPainter(image) image_painter.setPen(QColor("#bdbfc0")) image_painter.setBrush(QColor("#bdbfc0")) polygon = QPolygon() polygon.append(QPoint(0, r.width() * 0.5)) if element == QStyle.PE_IndicatorArrowDown: polygon.append(QPoint(size, size * 0.6)) polygon.append(QPoint(size / 2, size * 0.1)) else: polygon.append(QPoint(size, size * 0.5)) polygon.append(QPoint(size / 2, size * 0.9)) image_painter.drawPolygon(polygon) image_painter.end() pixmap = QPixmap.fromImage(image) painter.drawPixmap(r.x() + (r.width() - size) / 2, r.y() + (r.height() - size) / 2, pixmap) else: QProxyStyle.drawPrimitive(self, element, opt, painter, widget)

Regards!