this is roughly sufficient to recreate the website as it currently is
- elements:
- document
- html
- head
- title
- base
- link (variants that must be unique nested under `head` directly)
- canonical
- meta (same as for link):
- charset
- viewport
- author (can be multiple, but still unique in aggregate for a document)
- description
- global attributes:
- class
- hidden
- id
- lang
- style
- title
- element-specific attributes:
- href
- target
there's still a lot to do for a reasonably complete implementation, most
importantly everything concerning
- navigation
- top-level flow content (`div`, `article`, headings, `p`, ...)
- stylesheets
there's also some infrastructure to be arranged for easy but somewhat
safe switching between literal HTML and structured representations.
