[mooring]

I am trying to setup a heading or other formatting code so that I can break
my document into parts separated by a heading like this:

----------- Chapter 1 -----------

Where the two lines are a % of page width; move with changes in the text
("Chapter 1"); and are centered vertically with the text in the middle. I
have seen this in documents, but I can't figure out how to do it in word.

Thanks in advance!