Examine source code of Starsatnight

{
  "name": "Night Sky",
  "manifest_version": 2,
  "version": "1.0",
  "theme": {
    "images": {
      "theme_frame": "kisspng-night-sky-desktop-wallpaper-star-night-5ab8f4835ca480.6625602215220706593795.png"
    },
    "colors": {
      "frame": "rgba(240, 242, 245, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)",
      "toolbar": "rgba(0, 0, 0, 1)",
      "bookmark_text": "rgba(22, 29, 224, 1)"
    }
  }
}