Examine source code of rectangular_rainbow

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "rectangle rainbow",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat-x"
      ]
    },
    "colors": {
      "toolbar": "rgba(3, 70, 48, 0.23)",
      "toolbar_text": "rgba(227, 201, 215, 0.8)",
      "frame": "rgb(4, 57, 63)",
      "tab_background_text": "rgb(245, 245, 245)",
      "toolbar_field": "rgba(96, 11, 35, 0.24)",
      "toolbar_field_text": "rgba(206, 183, 196, 0.8)",
      "tab_line": "rgba(237, 17, 94, 0.99)",
      "popup": "rgba(4, 55, 78, 0.88)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_loading": "rgba(237, 17, 94, 0.99)"
    }
  }
}