What is the most character-efficient way to increase CSS specificity?

Question

If I want to increase the CSS specificity of a rule, I tend to prefix with html, but I wonder if there are more concise ways of doing this?

(It may seem

Answer 1

I've seen a postcss library use :not(#\9) which is pretty short, increases specificity by one, and basically works on everything. Doesn't work with ie8 or less, but come on this is 2020