PySide6 modifies the "QTabWidget" style sheet to have rounded corners But it seems like the background still has right angles

Question

PySide6 modifies the "QTabWidget" style sheet to have rounded corners But it seems like the background still has right angles.

self.DialogueGroup_StackedWidget.setStyleSheet("QStackedWidget {"
                                                       "color: rgb(176, 224, 230);"
                                                       "background-color: rgba(41, 48, 83, 0);"
                                                       # "border-bottom-left-radius: 7px;"
                                                       "border-radius: 15px;}" 
                                                       )

I've been using Google for a long time but haven't found a suitable method