Main Content
This main column is wider than the sidebars using a larger flex value.
This main column is wider than the sidebars using a larger flex value.
All three boxes share the available width equally.
Flex 1 on each item creates equal-width columns.
Flexbox also keeps the column heights consistent.
This column controls the overall height of the section. The column on the right will always split its height evenly between the blue and green boxes.