How to change the styles of a block that has been moved to a new line?

Question

css

how to catch elements (blocks) wrapped on a new line and change their styles?
for example: a lot of square boxes that have a right and bottom border of 1px. you need to add a top border to all the blocks in the first line, and a left border to all the first blocks in the line. the result should be a table with all borders 1px thick.
(you need to achieve the effect border-collapse: collapse; for div with adaptive layout (it is not known how many blocks will be in a line, display: table - do not suggest) )

Answer 1

You can make margin-top:-1px - then the borders on adjacent lines will overlap