More compact design (more text on screen at once)

> perhaps smaller or different fonts option and smaller icons (I suppose I could just zoom out the page but that doesn't do a clean job)

I note that general theming is of interest to me, and this could be part of a theme. Plugins might be a good deployment mechanism for themes, so this is related to #26.

Requested by LateNightHacks via user review 2017/10/14.

Start by reviewing the extension's current interface and the related theming discussion in issue #26. Define how a more compact layout, font or icon options, and theme-based deployment should work before choosing an implementation. Done means a documented, consistent compact presentation is available without relying on browser zoom.

Written by the indexing model from the issue text.