The moinmoin theme we use replicates the roundup theme/layout used on:

  www.roundup-tracker.org
  issues.roundup-tracker.org

I made some changes in the 2.2.0 Roundup release to make the www.roundup-tracker.org
theme work better on mobile and pass some basic accessibility checks (aXe devtools, ARC 
toolkit).

  * stack the left hand menu above the content at a 960 px breakpoint. This is all done
    with css. It does not insert javascript to create a menu button to open the menu, so
    the menu is shown at all times. This was a quick hack to improve google's assessment
    for mobile.
  * changed css to keep content inside viewport by making code blocks scroll on
    overflow and allow long links and other connected words to break on any word boundary.
  * add a viewport statement to head of page

  * add nav and main landmarks to the html
  * add a skiplink to jump to the main landmark with id="main" also remove focus ring
    added by making the main landmark focusable.
  * contrast improvements for embedded code blocks by changing pygments to use borland
    style and explicitly setting background color for the blocks to lightyellow.

It would be nice to have wiki.roundup-tracker.org do something similar.
Some of these require some changes to the emitted HTML, so may or may not be doable.

issue2551056 has some other improvements suggested:

* The icons used are a bit outfashioned as modernized has icons which are better.
* Layout and icons can be improved overall like with the memodump. 
https://moinmo.in/ThemeMarket/memodump

The memodump theme is responsive. Not sure how much work would be needed to replicate
a matching look using it is unknown.

This issue replaces 2551056.