Ask HN: Future Proof Website Columns?

I am pondering what I should use and decided to ask the collective to see if I can get some answers.

This concerns really simple content based website. No big styling, just a few columns.

So what does HN community recommend to make this future proof.

There are multiple options like flex, css columns, old style floats, etc...

What would you recommend to go with in 2019 and it'll stick to 2029 at least.