Examine source code of Light House...

{
  "name": "Light House...",
  "manifest_version": 2,
  "version": "5.0",
  "theme": {
    "images": {
      "theme_frame": "LightHouseH1.jpg"
    },
    "colors": {
      "frame": "rgba(166, 195, 230, 1)",
      "tab_background_text": "rgba(0, 0, 0, 1)",
      "toolbar": "rgba(0, 0, 0, 0)",
      "bookmark_text": "rgba(0, 0, 0, 1)",
      "toolbar_field": "rgba(166, 195, 230, 0.06)",
      "toolbar_field_text": "rgba(0, 0, 0, 1)",
      "tab_line": "rgba(0, 0, 0, 1)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9494595b-700c-49b6-a4c4-43f33edd3f96}"
    }
  }
}