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margin-top-collapse: auto | nocollapse | collapse | discard; margin-break: auto | keep | discard;
margin-*-collapse is the standard “I want to control whether margins collapse” rule that people request all the time. The “discard” value helps with the use-case where the first block in a table-cell throws away its top margin.
margin-break is for when elements break across something (page, column, flexbox-line) and you want to keep or discard the relevant margins.