Examine source code of Grey Darkly

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "DARKLY",
  "theme": {
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(50, 54, 57)",
      "bookmark_text": "rgb(224, 224, 224)",
      "frame": "rgb(50, 54, 57)",
      "tab_background_text": "rgb(225, 225, 225)",
      "toolbar_field": "rgb(57, 63, 69)",
      "toolbar_field_text": "rgb(231, 231, 231)",
      "tab_line": "rgb(79, 146, 229)",
      "popup": "rgb(50, 54, 57)",
      "popup_text": "rgb(224, 224, 224)",
      "tab_loading": "rgb(231, 231, 231)",
      "ntp_background": "rgb(50, 54, 57)",
      "ntp_text": "rgb(224, 224, 224)",
      "popup_highlight": "rgb(79, 146, 229)",
      "button_background_active": "rgb(79, 146, 229)",
      "toolbar_field_highlight": "rgb(79, 146, 229)",
      "toolbar_field_border_focus": "rgb(79, 146, 229, 0.8)"
    }
  }
}