This example shows two different ways of building your page up from shared parts.
The first example uses what we commonly call 'markup inheritence',
and the second example shows how to achieve roughly the same
Compare the examples and decides what works best for you. You will find that markup
inheritance is usually easier to work with, and you'll rarely have the need to work with
borders. But in some cases borders make sense, and can be a little bit more flexible.
Also note the use of panels and component replacement to switch the banner.
Component replacement can be a powerful alternative to navigating between pages.