Examine source code of Fierce

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Fierce",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(255, 191, 200, 0.08)",
      "toolbar_field": "rgba(255, 255, 255, 0)",
      "toolbar_field_text": "rgb(240, 240, 240)",
      "tab_line": "rgb(254, 217, 120)",
      "popup": "rgb(25, 4, 37)",
      "popup_text": "rgb(223, 212, 255)",
      "tab_loading": "rgb(254, 217, 120)",
      "bookmark_text": "rgb(222, 211, 252)",
      "frame": "rgb(25, 4, 37)",
      "tab_background_text": "rgb(231, 198, 213)"
    }
  }
}