Examine source code of NightFox

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "NightFox",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 76, 117)",
      "toolbar_text": "rgb(199, 199, 199)",
      "frame": "rgb(0, 43, 70)",
      "tab_background_text": "rgb(158, 158, 158)",
      "toolbar_field": "rgb(0, 39, 62)",
      "toolbar_field_text": "rgb(158, 158, 158)",
      "tab_line": "rgb(138, 146, 219)",
      "popup": "rgb(0, 0, 0)",
      "popup_text": "rgb(165, 165, 165)",
      "tab_loading": "rgb(138, 146, 219)"
    }
  }
}