Css and javascript confusion on my part

I am clearly too stupid to understand this article because I do not have a clue what they are on about.

Is there actually any debate that css should not be used at all and replaced by javascript?
If so how would that even work, or am I reading this article wrong.

I am more of a php / mysql backend developer than I care to admit and have very limited javascript knowledge, but do know html and css well too for front end, which bootstrap helps with tremendously. So the crux of my question is, I never imagined replacing css with javascript for even a moment, is this even possible and is there any reason or big advantage in using javascript instead of css.