All Black Youtube

manifest.json

{
  "name": "All Black Youtube",
  "description": "Pitch Black Youtube",
  "version": "0.0.1",
  "manifest_version": 3,
  "content_scripts": [
    {
      "matches": ["*://*.extensions/*"],
      "css": ["styles.css"]
    }
  ],
  "permissions": []
}

styles.css

body, ytd-app, ytd-masthead {
  --yt-spec-brand-background-solid: black !important;
  --ytd-searchbox-background: black !important;
  --yt-spec-base-background: black !important;
  --yt-spec-raised-background: black !important;
  --yt-spec-general-background-a: black !important;
  --yt-spec-general-background-b: black !important;
  --yt-spec-general-background-c: black !important;
  --yt-spec-brand-background-primary: black !important;
  background: black !important;
}

.html5-video-container {
  height: 100%;
  width: 100%;
  top: 0px;
  left: 0px;
}

#player-theater-container:not(:empty) {
  max-height: none !important;
  width: 100% !important;
  height: calc(100vh - 64px) !important;
}