Re: colours for bullets - this one is simple, works, & addresses

>> You are mixing the document flow with the page layout flow. They
>> are separate objects.
>> Conceptually:
>>   document tree  --+----> page layout flow --> rendered representation
>>                    /
>>   stylesheet     -+
>Mixing flows? Like, 'stirring things up'? I believe that, structurally,
>paragraphs can have siblings; that a table or a list can be a sibling
>of a paragraph because these elements may relate specifically to that
>paragraph. But it appears that the rules of the document tree don't
>allow such a relationship. Am I wrong?

No. Paragraphs can have siblings, table rows can have siblings,
and there is most certainly a tree.

However, that relationship is completely separate from the tree of
formatting objects produced by applying the transformation represented
by a stylesheet to the tree, which is also different from the tree of 
display areas.