grid-template-rows: 50px 100px

A row track is created for each value specified for grid-template-rows . Track size values can be any non-negative, length value ( px , % , em , etc.)

Items 1 and 2 have fixed heights of 50px and 100px .

Because only 2 row tracks were defined, heights of items 3 and 4 are defined by the contents of each.