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CSS CSS Layout Basics Getting Started with CSS Layout Why Vertical Margins Collapse

Posted by Victor Mercier
Victor Mercier
14,667 Points

Vertical Margin Collapsing

Is someone able to make me a summarize about Vertical Margin Collapsing. Please tell how it happen and why does this happen. Please be clear because I am mixed up! Thanks in advance.

1 Answer

Steven Parker
Steven Parker
231,269 Points
Steven Parker
Steven Parker
231,269 Points

Margins are combined ("collapsed") by the browser so that the total margin is the same as single largest one. This happens in 3 cases:

  1. The bottom margin of one element is combined with the top margin of the next (sibling) element
  2. The top margins (or bottoms) of a parent and child element are combined
  3. The top and bottom margins of a single element with no contents are combined

That's the short summary. For more details, see the MDN page on Mastering margin collapsing.