le CSS:
.menu {
list-style: none;
}
body#homepage li#home a, body#page1page li#page1 a {
background: #fc3;
}
la page index.htm:
<body id="homepage">
<ul>
<li id="home"><a href="index.htm">Home</a></li>
<li id="page1"><a href="page1.htm">Page 1</a></li>
</ul>
la page page1.htm:
<body id="page1page">
<ul>
<li id="home"><a href="index.htm">Home</a></li>
<li id="page1"><a href="page1.htm">Page 1</a></li>
</ul>