Examine source code of Dark trees theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Forest",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(0, 0, 0, 0.37)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(123, 123, 128)",
      "tab_background_text": "rgb(215, 226, 239)",
      "toolbar_field": "rgba(35, 23, 20, 0.59)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(192, 192, 192)",
      "popup": "rgb(128, 129, 134)",
      "popup_text": "rgb(215, 226, 239)",
      "tab_loading": "rgb(192, 192, 192)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{c95dae4c-b0a0-4f91-bac0-14ebbfda9984}"
    }
  }
}