Different users on sl have diffrent xp points in css how is it possible

Question

Different users on sl have diffrent xp points in css but we cant challange other users in css. So how is it possible to have different xp points in such a language we cant challenge.

Answer 1

comment on the lessons.......
you will get xp through badges!!!!!!

Answer 2

you loss xp when you give wrong answers during lessons. also many people use their xp's in the lessons while answering the question for a clue.

Answer 3

Thnx bro