How to make blocks in the menu one after another, without indentation?

Question

css

There is a menu code with
Codepen
styles. The sides are made on flex and follow each other, while it is clear that there is an empty space between the first and third. How to remove it and pull the third block higher? Those. so that the blocks simply follow each other in two columns with a transfer. If there is a solution not on flex, then it will also be good

Answer 1

https://codepen.io/BormotunJedy/pen/oNWWOew
Remove margin-top from .parent and ul. Remove padding from ul.
If the menu should be vertical then nowrap. If horizontal to columns, then flex-direction:column;