// home 의 slug(url) fetch
* [_type == 'home'][0]{'mainPostUrl': mainPost -> slug.current}

// post fetch
* [_type == 'post']{
  title, 
  subtitle, 
  createdAt, 
  'content': content[]{
    ...,
    ...select(_type == 'imageGallery' => {'images': images[]{..., 'url': asset -> url}})
  },
'slug': slug.current,
'thumbnail': {
  'alt': thumbnail.alt,
  'imageURL': thumbnail.asset -> url
},
'author': author -> {
  name,
  role,
  'image': image.asset -> url
},
'tag': tag -> {
  title,
  'slug': slug.current
}
}