first make a css sheet. new/ page then there is a menu selection for
"normal style sheet" just make one and save it in your web.
go back to the page/ pages you want it linked to and click format/ style
sheet links and link your page with the .css file your created before.
Now, anything you write (css selectors, etc. ) on the .css file will be
linked to the html page.
You'll need to say specifically what you want to change "formating wise" and
post or search. there is a syntax to this stuff but it's not so bad and it
is a lot of bang for the buck see
www.csszengarden.com and see what just the
style sheet is capable of changing visually by browsing the "all pages"
index.
I'm sure what you want to do will require nothing near that amount of work.
you can even view the .css sheets that cause the changes. you will probably
not require more than a few lines.
HTH