First you must create your own style sheets -- it's quick and easy if you go to "File", New > Page, click "Style Sheets" tab and double click one, save it as your own (I just put my initials in front of the style name).
Load this page in "normal" view, click on "Format" in the main menu, click on "Style Sheet Links" and choose one of your new style sheets.
The following text appears within the html tag angle brackets just before the /head tag at the beginning section of each of your documents:
link rel="stylesheet" type="text/css" href="dmsweets.css"
You can test several by just changing the href file name to match your saved css files (they should appear in the "Folder List" on the left).
When you find one you really like (you can make adjustments to meet your design needs), use it in your pages for that nice consistent look.
|Cell 1||Cell 2|
|Cell 3||Cell 4|