I have never used stylesheets before.

I am using the following style. How can I reference this in a style sheet so that I do not have to keep retyping it when I need to use it ?

<style rollover>
A:link {color: #003E71; text-decoration: none}
A:visited {color: #003E71; text-decoration: none}
A:hover {color: RED; text-decoration: none}
</style>