I was kinda surprised that this method wasn't included in the article. While I use flexbox for centering most of the time, I still find myself resorting to the absolute positioning way sometimes.

Centering like this can make your element blurry on non-hidpi screens, because transforms are not snapped to the pixel grid like layout properties, and 50% can sometimes land on a subpixel

Is this still relevant? I thought browsers had proper support for sub-pixels now.

I think this was exclusive to Chrome.

https://issues.chromium.org/issues/40431598

Seems like they managed to kinda fix it in some cases, but some of the reproductions provided in the issue tracker are still working, so I would be careful

What do you do when position isn’t absolute?

Then I use one of the approaches listed. However, I find that usually I want absolute positioning when centering either horizontally or vertically.