Safari is first to drop text-box in CSS, which plenty of people are excited for as it takes care of aligning text in many cases without the use of fragile magic numbers. They say:
Now you can declare which font metric you want the browser to consider the edge of the text box when calculating layout
Jason Bradberry has a wonderfully deep article and showcases one of the big use cases (non jacked up button centering).
Like Robin Rendle says:
I’m always fighting the text-box when it comes to buttons in an interface and so hopefully this property fixes all that.
This line of code is about to be in every single stylesheet.
h1, p, button {
text-box: trim-both cap alphabetic;
}