If you used the iRp app on your phone or tablet on stage, you could display your charts in dark mode etc.
As an alternative to pdf consider using a screenshot image.
I think the iRp pdf creator only generates black text on a white background.
PDF’s are usually made to send to someone who doesn’t use iRp so they can PRINT charts.
If they tried to print a “white text, black background” chart they’d really burn through their printer’s ink supply.
)BOB