By what principle is the value calculated in vw?

Question

css

This site https://evilmartians.com/ uses an adaptive font value and in general for most selectors, padding, etc. For example, for html the font-size is 1.6666666666666667vw/1.2
What is the calculation principle? Isn't it done by hand? Are there any scripts/modules for this?
In general, how to competently switch to adaptive values ​​with px, em, etc.?

Answer 1

vw - viewport width
From my experience, I calculate the font like this:
Take the desired font size in pixels and divide by 16