Examine source code of simple dark academia

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "dark academia",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-039-717a66ba4d455686088c80f391cb3264.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(137, 135, 124)",
      "toolbar_text": "rgb(250, 243, 218)",
      "frame": "rgb(156, 153, 141)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(91, 89, 83)",
      "tab_line": "rgb(91, 89, 83)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(0, 0, 0)",
      "tab_loading": "rgb(91, 89, 83)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9071bb30-a6f8-4ce4-bfb9-d2ac8aee07c0}"
    }
  }
}