<!DOCTYPE html>
<html>
<head>
<style type='text/css'>
.focusNode {
background-color: orange;
}
.focusNode ul {
background-color: white;
}
</style>
</head>
<body>
<ul>
<li>root1</li>
<li class="focusNode">root2
<ul>
<li>sub1</li>
<li>sub2</li>
<li>sub3</li>
</ul>
</li>
<li>root3</li>
</ul>
</body>
</html>