[css21] Collapsing margins

Can anybody comment following [1]:

If the top and bottom margins of a box are adjoining, 
then it is possible for margins to collapse through it. 
In this case, the position of the element depends on its 
relationship with the other elements whose margins 
are being collapsed. 

What exactly means: "top and bottom margins of a 
box are adjoining"? 
Top and bottom margins of a box are 
adjacent to each other?

If yes then there is only one case when it is possible - 
when block has computed value of height equals to zero.

And also "then it is possible" implies some indetermination.
Is this the intention?

OT: Is it possible in principle to define margin collapsing 
in terms of :first-child or something like this?

Andrew Fedoniouk.

[1]  http://www.w3.org/TR/CSS21/box.html#collapsing-margins

Received on Sunday, 19 February 2006 00:10:27 UTC