Examine source code of celestial-theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Celestial",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(25, 25, 32)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(149, 150, 154)",
      "toolbar_field": "rgb(11, 12, 15)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(205, 76, 106)",
      "popup": "rgb(11, 12, 15)",
      "popup_text": "rgb(154, 156, 158)",
      "button_background_active": "rgb(14, 15, 19)",
      "button_background_hover": "rgb(14, 15, 19)",
      "icons_attention": "rgb(190, 161, 132)",
      "icons": "rgb(154, 156, 158)",
      "popup_border": "rgba(255, 255, 255, 0)",
      "popup_highlight_text": "rgb(255, 255, 255)",
      "popup_highlight": "rgb(0, 0, 0)",
      "sidebar_border": "rgba(0, 0, 0, 0)",
      "sidebar_highlight_text": "rgb(255, 255, 255)",
      "sidebar_highlight": "rgb(0, 0, 0)",
      "sidebar_text": "rgb(154, 156, 158)",
      "sidebar": "rgb(14, 15, 19)",
      "toolbar_field_border_focus": "rgba(8, 0, 0, 0)",
      "tab_loading": "rgb(205, 76, 106)"
    }
  }
}