The following code shows how to set hover background color.
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css"
href="netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css">
<link rel="stylesheet" type="text/css"
href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css">
</head><!--from ww w .ja v a 2s. c o m-->
<body>
<div class="row-fluid span12" style="width: 300px">
<div class="span6 btn" style="background-color: #ff0;">button1</div>
<div class="span6 btn" style="background-color: #f0f;">button2</div>
</div>
</body>
</html>