Ever since I started using a 4K monitor, I noticed that I have to adjust browser zoom almost for every site where I wanted to read content and not just glance at some excerpt. Looking closer at CSS styles on some of those sites I found that most of them used pixel unit sizes for pretty much everything, including fonts. I was puzzled at first by the widespread use of a technique that cannot compute sizes in a predictable way across various displays and devices, but further investigation confirmed that it was done on the advice of the CSS specification.