We would like to know how to before: add another border.
<!--from w w w. j a va 2s .c o m-->
<!DOCTYPE html>
<html>
<head>
<style type='text/css'>
#borders {
position: relative;
z-index: 10;
padding: 30px;
background: #fff;
border: 2px solid #390;
}
#borders:before {
content: "";
display: block;
position: absolute;
z-index: -1;
top: 2px;
left: 2px;
right: 2px;
bottom: 2px;
border: 2px solid #36F
}
</style>
</head>
<body>
<div id="borders"></div>
</body>
</html>
The code above is rendered as follows: