[ENH] Add UI elements for document viewer

[smokestacklightnin]

Feature description

As discussed in #466, it remains to add the UI elements for a document viewer. This issue tracks that specific task.

The guide for what to do can be found in #486, although my strong recommendation for whomever works on this issue is to create a new branch off of upstream/main and copy or adapt the relevant portions of #486.

[staru09]

Is this available to work?