Examine source code of Simple Bold dark edition

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Simple Dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(19, 20, 21, 0.05)",
      "toolbar_text": "rgb(58, 54, 54)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgba(255, 255, 255, 0.64)",
      "toolbar_field_text": "rgb(32, 30, 30)",
      "tab_line": "rgb(9, 183, 224)",
      "popup": "rgb(135, 135, 135)",
      "popup_text": "rgb(7, 7, 7)",
      "tab_loading": "rgb(9, 183, 224)"
    }
  }
}