How can we find simplicity in CSS?

The history of CSS is full of experiments with different attempts to solve common problems - one of the biggest being - how can layout and position content in a webpage.

To find simplicity we need to work out a subset of CSS that can solve all the problems we need to solve and allow us to avoid complexity.

For instance in modern web browsers it feels like the CSS grid layout supersedes all the previous attempts at solving this problem in a much more elegant way.