Removed some comments and layout

Produces sensible (but not perfect) results from different kinds of highlight markup.
The CSS code needs a major refactoring to eliminate duplication and superflous lines.

Fixed more layout details. Numbers of selectors still to be fixed.

Correected layout, order, values.

The added examples in `docs/index-test.md` extend the previous examplees of highlighting, documenting the required inout.