Nancy has it nailed here.
You have given us your styles and that's all well and good, but it shows nothing about what you have done in HTML and, how you set things up in HTML will really tell the story.
I note you're defining your #body as if though it had a width. There is an HTML element called "body" that does not need an ID (though you can attach an ID or a class to it). the <body> tag in HTML is supposed to take up your entire viewport. So you would enclose a #container within a body.
So generally what you would do is set up the attributes that will be the default with your body thusly:
body {
background-color: #003781;
color: #000000;
font: 100%/1.4 Verdana, Arial, Helvetica, sans-serif;
margin: 0;
padding: 0;
text-align: center;
}
Then you define your various text styles, like h1 through h4 (if needed) your paragraphs, your unordered lists, ordered lists and links (visited, hover, active, focus, etc.).
After that, establish your main container. You'll put your header, all of your columns and your footer inside that. Your main container will establish the width of your website.
Now, understand that what Nancy is telling you here is that this wheel has been invented many times. So picking something from Dreamweaver that will autoassemble is learning. Because it's heavily commented, you can read the comments and understand why everything goes where it goes.
As you are learning, you'll learn about navigation and how to insert that. You'll learn how a <div> gets its size and its height by placing things in them and watching as they either appear or don't. You'll learn how to insert more <div> tags to place things where you want them.
None of Dreamweaver's built-in templates really set you up for navigation, which is its own fun learning curve. Need drop-down menus? Take a tutorial or purchase something that inserts (and works) perfectly from Project VII. In the meantime, you'll be learning as you go and you'll learn from the masters, not from some book.
And you won't get frustrated when it doesn't work, because if you really follow what's going on, you'll begin to understand HTML and CSS.
