I tried this:
Qt Code: 
  1. void ShiftOpGroup::setThisStyle()
  2. {
  3. 	QString style = 
  4. 		"QPushButton { "
  5. 			 "color: white; "
  6. 			"background-color: "
  7. 				"qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
  8. 				"stop: 0 #08080a, stop: 1 #66777a); "
  9. 			"border: 6px solid white; "
  10. 			"border-style: sunken; border-width: 2px; "
  11. 			"border-radius 6px; border-color: white; }"
  12. 		"QPushButton:pressed { "
  13. 			"color: black; background-color: aqua;"
  14. 			"background-color: "
  15. 				"qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
  16. 				"stop: 0 #eaebfe, stop: 1 #76878a); "
  17. 			"border-style: raised; border-width: 3px;"
  18. 			"border-radius 4px; border-color: black;}";
  19.  
  20. 	this->setStyleSheet(style);
  21. }
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... but that does nothing.

What I've had to do is to connect the "pressed" and "released" signals of each QPushButton to a slot that sets the style.

Like this ...

Qt Code: 
  1. class ShiftOpGroup : public QWidget
  2. {
  3. 	Q_OBJECT
  4. public:
  5. 	explicit ShiftOpGroup(QPoint *start, QWidget *parent = 0);
  6.  
  7.     :
  8. 	QButtonGroup *buttonGroup;
  9.     :
  10.  
  11. public slots:
  12. 	void sbPressed(int);
  13. 	void sbReleased(int);
  14.     :
  15. }
  16.  
  17.  
  18. ShiftOpGroup::ShiftOpGroup(QPoint *start, QWidget *parent) :
  19. 	QWidget(parent)
  20. {
  21.        :
  22. 	connect(buttonGroup, SIGNAL(buttonPressed(int)), this, SLOT(sbPressed(int)));
  23. 	connect(buttonGroup, SIGNAL(buttonReleased(int)), this, SLOT(sbReleased(int)));
  24.        :
  25.  
  26.  
  27. void ShiftOpGroup::sbPressed(int pbIndex)
  28. {
  29. 	QString style =
  30. 			"color: white; "
  31. 			"background-color: "
  32. 				"qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
  33. 				"stop: 0 #08080a, stop: 1 #66777a); "
  34. 			"border: 6px solid white; "
  35. 			"border-style: sunken; border-width: 2px; "
  36. 			"border-radius 6px; border-color: white; ";
  37.  
  38. 	pShiftButtons->widgetList[pbIndex]->setStyleSheet(style);}
  39.  
  40. void ShiftOpGroup::sbReleased(int pbIndex)
  41. {
  42. 	QString style =
  43. 			"color: black; background-color: aqua;"
  44. 			"background-color: "
  45. 				"qlineargradient(x1: 0, y1: 0, x2: 0, y2: 1,"
  46. 				"stop: 0 #eaebfe, stop: 1 #76878a); "
  47. 			"border-style: raised; border-width: 3px;"
  48. 			"border-radius 4px; border-color: black; ";
  49.  
  50. 	pShiftButtons->widgetList[pbIndex]->setStyleSheet(style);
  51. }
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I have to do that for every QPushButton in every subclass.

There's got to be a better way.

I tried doing it application-wide, and subclass-wide, but it does not seem to work unless I capture the "pressed" and "released" signals for each QPushButton.