Get theme details.

Example response

{
  "data": [
    {
      "id": 1,
      "type": "themes",
      "href": "/v1/themes/1",
      "attributes": {
        "name": "Cars",
        "color": "#C5C5C5",
        "symbol": "https://kurozora-cdn.app/1/symbol.png",
        "description": "Stories that feature cars at the center of attention or involve racing.",
        "isNSFW": false
      }
    }
  ]
}