Comment by bhdzllr

No, you don't need it if you use block-level elements (like div, header, nav, main, footer). Block elements always start on a new line and are therefore always one after the other in a column direction. This is part of HTML and will not go away.

Here is a simple example without styling:

https://jsfiddle.net/3g71hLf0/2/

And with some styling:

https://jsfiddle.net/3g71hLf0/1/