How to make such a thing between blocks?

Question

css

How to make such a thing between blocks? Absolute positioning is not possible. With relatively, such garbage appears (with the positioning itself, everything is fine, but the text bounces up, is repaired by an increase in padding, but then the size absolutely changes). How to fix relative? Or how to do it differently?

Answer 1

Position relative to the blue block, absolute and bottom to the gray block with a minus ... Or through before after