/ recognize id and options for the doctitle (aka header); should be part of Asciidoctor core
- (attr 'header-opts').split(',').each {|opt| header.set_option opt unless header.option? opt } if attr? 'header-opts'
- header.id = attr 'header-id'
- _bg_img = _style = nil
- if (_preamble = pluck_first context: :preamble)
  - unless (_result = _preamble.find_by context: :image, role: 'canvas').empty?
    - (_bg_img = _result[0]).set_attr 'skip-option', ''
    - _style = %[background-image: url(#{image_uri _bg_img.attr(:target)}); background-size: #{(_bg_img.roles & %w[cover contain])[0] || 'cover'}; background-repeat: no-repeat]
section.title id=header.id class=[role, ('image' if _bg_img)] style=_style data-title='' data-bespoke-backdrop=(attr 'header-backdrop-role')
  - content_for :content
    - if (_title_obj = doctitle partition: true, use_fallback: true).subtitle?
      header
        h1=slice_text _title_obj.title, (_slice = header.option? :slice)
        h2=slice_text _title_obj.subtitle, _slice
    - else
      h1=slice_text _title_obj.title, (header.option? :slice)
    =_preamble ? _preamble.content : nil
    / TODO move footer to include file
    - if attr? :author
      footer
        / TODO handle multiple authors
        p.author
          span.personname
            span.firstname=>attr :firstname
            - if (attr? :middlename)
              span.middlename=>attr :middlename
            span.surname=attr :lastname
          - if (attr? :position) || (attr? :organization)
            =newline
            span.affiliation
              - if attr? :position
                span.position=>attr :position
              - if attr? :organization
                span.organization=attr :organization
          - if attr? :avatar
            =newline
            img.avatar src=(image_uri attr :avatar) alt=(attr :author)
          - if (attr? :twitter) || (attr? :email)
            =newline
            span.contact
              - if attr? :twitter
                span.twitter=>attr :twitter
              - if (attr? :email)
                - if (((_val = attr :email).start_with? 'http://') || (_val.start_with? 'https://'))
                  span.url=_val[((_val.index '//') + 2)..-1]
                - else
                  span.email=_val
        /- if attr? :hashtag
        /  p.meta: span.hashtag=attr :hashtag
  - if (header.option? :enclose) || (document.attr? 'enclose-option')
      - _notes = _preamble ? (pluck_first context: :sidebar, role: 'cue') : nil
      .content
        - yield_content :content
      =_notes ? _notes.convert : nil
  - else
    - yield_content :content