How to change the border color of each cell without changing background color!

[fres]

I want to change the border color of the tableWidget without changing the main color.

This is what I have in the tableWidget:

And, when i wrote the styleSheet :

QTableView::item {
border: 1px solid white;

}

This is what happens:

But, I don't know how to change any border color of the cell WITHOUT changing the color of the cell. I still want the item(0,0) to be in black, and the item(0,1) to be in white...
Thank you so much !!

[fres]

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