Hello,
I am fairly new to CSS and created a layout with a fixed navigation and liquid header, footer and content divisions. It looks great in Google Chrome but when I test it in Firefox or IE7 it is rendered differently.

Here is my layout:
http://www.bigoakexxon.com/example.htm

As you can see, when opened with Firefox the problem is only with the margins. With IE7 the problem is with the min-height property and the margins it looks like. I am aware that IE does not like "min-height" and instead uses height as min-height.
I could probably make the layout look nice in any of these browsers but not all of them with the same code.
Any help or advice on my coding would be greatly appreciated!

Thanks so much

IE7 supports min-height, but IE6 does not.

Having said that, you're missing a DOCTYPE so IE might be in quirks mode. I would make your page validate first (http://validator.w3.org/) before trying anything else so IE will render in standards mode.

also you may find it helpful to use a meta tag to tell IE which standards mode to render in.

What does validating my site do?
What is the purpose of the DOCTYPE command?
These things are new to me. I'm not following.

DOCTYPE declares what kind of HTML is being used. i.e XHTML 1.1 Strict, HTML 4.0 Transitional, etc.

Here's a quick reference guide:
http://htmlhelp.com/tools/validator/doctype.html

To get around the min-height in IE6 you would add this to your CSS

* html #html-element-name {
height: 300px; // whatever your value for min-height is
}