Information Technology Systems & Services
Use External Stylesheets
Place your CSS rules in an external stylesheet, so that they do not need to be downloaded again each time a new page is loaded.
In-line stylesheets currently work but try to avoid them because they are deprecated in XHTML 2.0. It is better to use embedded stylesheets than in-line stylesheets. But it is best yet to use linked or imported stylesheets, since they naturally separate content and presentation which is a core concept of web standards.
Reference:
"In general, the safest and most useful form of style sheets are external style sheets, in which the style rules are set up in a separate file." - The Access Board.