CSS stylesheet not being recognized
I am new to Dreamweaver and am building a new site. I have set up the basic site with my main.html page, my styles.css page, and my folders. I want the title and the topnav to float to the left and right respetively. Then I will insert a banner, and then I want a main content panel to float to the left and a sidebar to float to the right. I thought I had created the necessary html code and the css code, but the divs are not floating. Could someone please look at my html and css codes below and tell me what I am doing wrong?
==================================================
<!doctype html>
<html>
<head>
<link href="CSS/styles.css" rel="stylesheet" type="text/css">
</head>
<body>
<div id="name">
<h1>JA Weir Associates </h1>
<h2>Curtain Wall Consulting</h2>
</div>
<div id="topnav">
<ul>
<l1>Home</l1>
<l2>About</l2>
<l3>Services</l3>
<l4>Gallery</l4>
<l5>Contact</l5>
</ul>
</div>
<div id="banner">
</div>
<div id="content">
<p>This will be the Main Heading.</p>
<p>This will be the text in the content area.</p>
</div>
<div id="sidebar">
<p>This will be in the sidebar.</p>
</div>
<div id="footer">
<p>Copyright 2018. All rights reserved</p>
</div>
</body>
</html>
============================================
/* CSS document*)
*{ margin:0; padding:0: border:0}
#name { width:300px; float:left; }
#topnav { width:500px; float:right; }
#banner { }
#content { width:500px; float:left; }
#sidebar { width:300px; float:right; }
#footer { }
