Examine source code of Super Theme by nee!

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Super Theme",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-001-9c6d74e14860e77ee6f8f43e824bff25.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(41, 130, 87)",
      "toolbar_text": "rgb(25, 227, 80)",
      "frame": "rgb(59, 135, 135)",
      "tab_background_text": "rgb(25, 227, 80)",
      "toolbar_field": "rgb(56, 240, 200)",
      "toolbar_field_text": "rgb(123, 127, 204)",
      "tab_line": "rgb(248, 112, 140)",
      "popup": "rgb(122, 253, 122)",
      "popup_text": "rgb(98, 102, 183)",
      "button_background_active": "rgb(0, 42, 198)",
      "button_background_hover": "rgb(84, 37, 215)",
      "frame_inactive": "rgb(196, 66, 146)",
      "icons_attention": "rgb(221, 11, 212)",
      "icons": "rgb(172, 193, 54)",
      "ntp_background": "rgb(40, 195, 195)",
      "ntp_text": "rgb(198, 123, 0)",
      "popup_border": "rgb(195, 178, 40)",
      "popup_highlight_text": "rgb(198, 123, 0)",
      "popup_highlight": "rgb(204, 137, 13)",
      "sidebar_border": "rgb(226, 226, 25)",
      "sidebar_highlight_text": "rgb(155, 38, 111)",
      "sidebar_highlight": "rgb(221, 25, 226)",
      "sidebar_text": "rgb(219, 18, 22)",
      "tab_loading": "rgb(248, 112, 140)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{96e5e2bf-ca83-4f5e-8eea-27bb104d3134}"
    }
  }
}