Examine source code of hubble deep field theme

{
  "name": "hubble deep field theme",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "hubble-ultra-deep-field-landscape.jpg"
    },
    "colors": {
      "frame": "rgba(255, 255, 255, 0)",
      "tab_background_text": "rgba(140, 140, 140, 1)",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(222, 222, 222, 1)",
      "toolbar_field": "rgba(69, 69, 69, 0.2)",
      "toolbar_field_text": "rgba(222, 222, 222, 1)"
    }
  }
}