can I remove or change background color subtitle/webvtt in html5

Question

I want to remove or change the background of the subtitles. I've changed the background-color and background but it doesn't work. can the background change?

::cue {
  color: red;
  background-color: blue; //or background: blue;
}

the subtitle color changes to red but the background doesn't change at all

Answer 1

I tried the following:

::cue {
  color: red;
  // take an absurd big outline, because background is only behind the text
  outline: 500px solid blue;
  // dont know why background-color is not working but background-image does the job
  background-image: linear-gradient(blue, blue);
}