Qt Creator Themes - Apply to widgets
When you change the theme of Qt Creator, the style of the widgets in the Qt Designer change accordingly. However the look of your application is not changed when you actually run it. My questions is, is it possible to use the theme style for some of your widgets? I would like to change the stylesheet of some of my widgets to give the same look as when I view them in the Qt Designer.
No that is unique to Creator. Its uses fusion as Style (the dark ones) and then custom colors on top.
You can have look in
So it should be possible to replicate the look.