i want to creat a three column site(with the right column coming from top like the hearder div). please, can somebody help me check if i got everything fine with the css codes?

css
#body {
padding: 5px;
width: 980px;
margin: 20px 20px;}
#pagewrap {
padding: 5px;
width: 645px;
margin: 20px auto;
}
#header {
height: 100px;
padding: 0 15px;
}
#content {
width: 170px;
float: left;
padding: 5px 15px;
margin: 5px 0px 0px 0px;
}

#middle {
width: 394px;
float: left;
padding: 5px 15px;
margin: 5px 5px 5px 5px;

}

#sidebar {
width: 150px;
padding: 5px 15px;
float: right;
margin: -140px -20px 5px 10px;
}
#footer {
clear: both;
padding: 0 15px;
}

html

Responsive Layout

1st Content Area
This page

2nd Content Area
one another.

3rd Content Area

Footer
Footer text

thanks, your help will be appricaited.