How to add CSS to external HMTL file in Flash

Hello all,
Is there a way to call out an external HTML file into a text box in flash and have the HTML styled accordingly to a external CSS file.

I’ve seen it done before with a XML and .txt file but I’m not sure how to configure the HTML file. Do I still use all the html tags such as <html>, <head> and <body>. What if I want to style a particular paragraph by using a external css file?

I’ve tried several tutorials on scrolling text and external xml but none explain how to write up an html file. Please help! I’ve searched through everywhere and have not found an answer.