This particular grid library has a width of 12 columns. So every row needs to have columns add up to 12.

(You should probably use the <h1> element to define your article page in this block.)

This is the case even when you nest <div> elements. Below are more <div> elements with various classes that add up to 12.

col-6

col-3

col-3

A col-1

B col-11

C col-2

D col-10

E col-3

F col-9

G col-4

H col-8

I col-5

J col-7

K col-6

L col-6

M col-12