Examine source code of NiceFlower

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Flower",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(24, 74, 104, 0.95)",
      "toolbar_text": "rgb(220, 215, 173)",
      "frame": "rgb(89, 115, 74)",
      "tab_background_text": "rgb(218, 243, 225)",
      "toolbar_field": "rgba(247, 251, 234, 0.95)",
      "toolbar_field_text": "rgb(10, 3, 35)",
      "tab_line": "rgb(121, 168, 166)",
      "popup": "rgb(234, 247, 243)",
      "popup_text": "rgb(6, 29, 44)",
      "tab_loading": "rgb(121, 168, 166)"
    }
  }
}