Examine source code of Multicolor block theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "colorful theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(16, 29, 36)",
      "toolbar_text": "rgb(160, 221, 124)",
      "frame": "rgb(10, 255, 216)",
      "tab_background_text": "rgb(254, 254, 254)",
      "toolbar_field": "rgb(227, 255, 0)",
      "toolbar_field_text": "rgb(0, 14, 255)",
      "tab_line": "rgb(0, 14, 255)",
      "popup": "rgb(56, 69, 135)",
      "popup_text": "rgb(10, 255, 216)",
      "tab_loading": "rgb(0, 14, 255)"
    }
  }
}