Most (not all) of the style things that normally get put between the < style > tags, can be put into a textfile, with the extention .css (e.g. mysheet.css). The formatting of your webpages can be made easy this way, (i.e. to put most of it into a textfile), especially if you have a lot of pages.
So if you for example have to change the backgroundcolor of all your pages, by changing the style section, you just change your stylesheet, instead of changing all your pages one by one.
e.g.: open notepad and put the following into it:
BODY {
background-color : #BBDDFF;
border-color : #BBDDFF;
color : #001088;
}
Save it with the name : mysheet.css (or whatever name, as long as the extention is .css) in the same folder where you have your webpages.
In your webpages put the following in the HEAD section (between the <head> </head> tags)
<link rel="STYLESHEET" type="text/css" href="mysheet.css">
Try it and fiddle around a bit with the background-color and see how it affects all the pages that use the stylesheet.