The number of CSS and Javascript files doesn't really have much of an impact on how much resources a website uses. It's mostly a logistical decision. You can

The number of CSS and Javascript files doesn't really have much of an impact on how much resources a website uses. It's mostly a logistical decision. You can build a wasteful website with one (or zero) of them, and a slim one with dozens of js and css-files. There is a weak accidental correlation between these two things, but it's not necessary.