This is the header
This is the main content area.
Notice that the structural tags are behaving exactly like divs, i.e. the browser defaults are the same for the HTML structural tags as they are for the div's.
  1. each on their own line
  2. no space between them, i.e. a margin of 0
  3. adjacent borders remain separate

The above are true in Chrome, Edge, Firefox, and Opera.

Revised: 2/15/23