Hi there from what you are saying you want to have a white background same as the twitter bootstrap css design but you can't change the body to white.
So you need to find this code as your body has a class added to it's tag, find for this in your page template (should be just before the <body> tag):
<style type="text/css" id="custom-background-css">
body.custom-background { background-color: #d4d4d4; }
</style>
that is what you are looking for to change the background color.
EDIT:
Try finding and changing this:
.container {
background-color: #D4D4D4;
margin: 0px auto;
padding-right:24px;
padding-left:24px;
}
and this:
<style>
body {
padding-top: 60px;
}
</style>
Please also check your css file on the page http://www.bleep.io/contact.html as it's a broken link and it may be the cause of that:
<link href="assets/css/bootstrap-responsive.css" rel="stylesheet">