Examine source code of Dark theme i3

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "nix99",
  "theme": {
    "images": {},
    "properties": {},
    "colors": {
      "toolbar": "rgb(51, 51, 51)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(34, 34, 34)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(17, 17, 17)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(51, 51, 51)",
      "popup": "rgb(51, 51, 51)",
      "popup_text": "rgb(255, 255, 255)",
      "button_background_active": "rgb(119, 119, 119)",
      "button_background_hover": "rgb(119, 119, 119)",
      "ntp_background": "rgb(34, 34, 34)",
      "ntp_text": "rgb(255, 255, 255)",
      "popup_border": "rgb(34, 34, 34)",
      "tab_loading": "rgb(51, 51, 51)"
    }
  }
}