function Emph (emph)
  local content = emph.content
  if #content == 1
    and content[1].t == 'Span'
    and content[1].classes:includes 'mark-red' then
    return {
      pandoc.RawInline('latex', '\\colorbox{lightred}{'),
      content[1],
      pandoc.RawInline('latex', '}')
    }
  end
end