Examine source code of Just plane awesome.

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Just Plane Awesome!!!",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat-y"
      ]
    },
    "colors": {
      "toolbar": "rgba(255, 255, 255, 0.34)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(0, 145, 255)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(33, 116, 194)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(255, 255, 255)",
      "popup": "rgb(33, 116, 194)",
      "popup_text": "rgb(255, 255, 255)",
      "ntp_background": "rgb(0, 145, 255)",
      "ntp_text": "rgb(255, 255, 255)",
      "tab_loading": "rgb(255, 255, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{265ded60-6285-4a4f-9ea1-6d4fd05d63a6}"
    }
  }
}