How to partially specify a property in CSS?

Question

css

Hello. I want to partially change the frame (border) of a QComboBox widget in QtCreator (Qt 6, C++) using stylesheet.
Like here, I want, for example, to change only the thickness of the frame, and leave the rest as it is, by default. I try something like this: But it doesn't work. Is there any way to implement this at all?
border: 4px initial initial;

Answer 1

Is there any way to implement this at all?

No, the style is always completely replaced.

Answer 2

border-width: 4px

Answer 3

https://doc.qt.io/archives/qt-4.8/stylesheet-examp...