audio player caption color

I use the Twenty Seventeen theme and want to switch to the theme’s dark setting.
However, the captions under my audio player are then almost the same as the background color, which makes them very hard to read.
I found some additional CSS to change the figcaption, but this doesn’t change the color of the captions with the audio player, only with images.
I assume there must be some CSS to do this, but I can’t find it.

Any help would be very much appreciated.