Yes... it's that question again.. Progress bar colours

[Stevolution]

Hello
Only started using QT Designer today, and I am basically learning it through trial and error.
Progress is kinda OK.

But, I have Googled the world for a solution to changing the colour of a QprogressBar.

I can edit the items stylesheet and add: QProgressBar::chunk { background-color: rgb(255, 209, 42);}
This sets the portion of the progress bar to the yellow colour I need.

But, how the heck do you change the remaining portion of the progress bar to black? My background it black and I don't want to see the unused progress bar.

I did read that changing the style sheet of a ProgressBar can break it?

Any advice warmly received by today's newbie.