margin collapsing

1. Do vertical margins between a floated box and any other box collapse?
2. Do margins of absolutely and rel开发者_StackOverflowative boxes collapse?

1. Float margins don't collapse. According to the spec:

   Vertical margins between a floated box and any other box do not collapse (not even between a float and its in-flow children).

2. Absolute positioned margins don't collapse. According to the same spec:

   Margins of absolutely positioned boxes do not collapse (not even with their in-flow children).

No, margin collapses only between two adjacent block elements when they have margin towards each-other.