QComboBox pop-up styling

[mentalmushroom]

Hello. I'd like to know what is the way to customize QComboBox pop-up via QSS. Namely I want to remove the corners of the pop-up area, because in my case it is rounded.

This is the code I tried:

QWidget#myParentWidget QComboBox QAbstractItemView
{
	border-radius: 15px;
	background-color: red;
}

QWidget#myParentWidget QComboBox QAbstractItemView
{
	border-radius: 15px;
	background-color: red;
}

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It produces the result like this:
qcombobox.png
Although pop-up is rounded and filled with the proper background color there is still something in the background that I can't remove.

Also I'd like to know if it is possible to apply QSS style to the items of the pop-up area. The following code doesn't work:

QWidget#myParentWidget QComboBox QAbstractItemView::item
{
   border-color: green;
}

QWidget#myParentWidget QComboBox QAbstractItemView::item
{
   border-color: green;
}

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