interface Assets {
  fonts?: FontAsset[];
  images?: ImageAsset[];
  videos?: VideoAsset[];
  audios?: AudioAsset[];
  subtitles?: SubtitleAsset[];
}

{
  "assets": {
    "fonts": [
      {
        "id": "heading-font",
        "src": "https://fonts.googleapis.com/css2?family=Inter",
        "family": "Inter"
      }
    ],
    "images": [
      {
        "id": "logo",
        "src": "https://example.com/logo.png"
      }
    ],
    "videos": [
      {
        "id": "intro",
        "src": "https://example.com/intro.mp4"
      }
    ]
  }
}

{
  "type": "text",
  "style": {
    "fontFamily": { "$ref": "heading-font" }
  }
}

{
  "type": "image",
  "src": { "$ref": "logo" }
}