- Margin is a margin-collapse overlap
- In css, adjacent two boxes may be brothers might be the ancestral relationships, their margins can be combined into a single external border. This combination is referred to as margins folded manner, therefore, the outside distance referred combined into a folded margins.
- Folding Results follow these calculation rules:
When two adjacent margins are positive, the result is the folding of the larger value between them two
When two adjacent outer distance are negative, the result is a large folding absolute values of both
When two outside from a positive and negative, folding the two together and the result is