I am improving my css skills on w3schools, my question is what is the 
 reason `.col-2` is under `.col-6`? 

Isn't it suppose to be under `.col-3`? 

I have put float left so `.col-2` should go under `.col-3`, for over 1 hour looking for reason.

The [code](https://www.w3schools.com/code/tryit.asp?filename=G263VQV9ECJ0) will not run until you click the "Run" button in the Tryit Editor.