This is a 4 column and 8 column layout
col-4
col-8
This is a 3 column and 9 column layout
col-3
col-9
This is a 2 column 5 column 2 column 3 column layout (12/3=4)
col-2
col-5
col-2
col-3
Use `col-auto` for Columns that shrink to fit their content:
col
col-auto
col-auto
col
col
col