what is cubic-bezier(n,n,n,n)

Answer 1

Cubic-bezier curve mathematicaly describes speed patterns of animations. It is defined by four points - starting point, end point and their respecitve handles.
For animation purposes coordinates of starting and end point are (0,0) and (1,1) respectively. Handles define the shape of the curve between starting and end point. First two values in cubic-bezier(n,n,n,n) are for starting point handle and the other two are for end point handle.
The math behind the function is complicated and you basicly do not need it for everyday use. Better try few configurations on http://cubic-bezier.com/

Answer 2

I donno