safari-video-player-track-override.css

/* DIV in the Shadow DOM in Safari, has white-space:pre so text doesn't wrap */
::-webkit-media-text-track-display {
   white-space: normal !important;
}
/* These overrides should work but don't seem to be working at all, not sure why */
::-webkit-media-text-track-display-backdrop {
   background-color: black !important; /* default: rgba(0, 0, 0, 0.5) */
}
/* SPAN inside the track-display container, has a forced color, better to not mess with it? */
::cue {
  color: yellow !important;
}