Hallo Norbert,
so zum Beispiel:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title> new document </title>
<style type="text/css">
#nav {
list-style: none;
margin:0px;
padding:0px;
}
#nav li {
float: left;
}
#nav li a {
padding: 6px;
display: block;
text-align: center;
background: #F00;
border-right: 2px solid #00f;
}
#nav li a:hover {
background-color: #0f0;
}
</style>
</head>
<body>
<ul id="nav">
<li><a href="#">schmal</a></li>
<li><a href="#">breit breit breit</a></li>
<li><a href="#">schmal</a></li>
</ul>
</body>
</html>
