Examine source code of Dark Theme

{
  "name": "Dark Theme",
  "manifest_version": 2,
  "version": "4.0",
  "theme": {
    "images": {
      "theme_frame": "back.png"
    },
    "colors": {
      "frame": "rgba(33, 33, 33, 1)",
      "tab_background_text": "rgba(247, 235, 236, 1)",
      "toolbar": "rgba(22, 22, 22, 1)",
      "bookmark_text": "rgba(172, 159, 187, 1)",
      "toolbar_field": "rgba(33, 33, 33, 1)",
      "toolbar_field_text": "rgba(172, 159, 187, 1)"
    }
  }
}