wyg.css
html, body {
height: 100%;
width:100%;
background:red;
margin:0;
padding:0;
}
#wyg {
background: #6666AA;
height:100%;
width:350px;
position:fixed;
top:0;
left:0;
bottom:0;
}
#site {
background:green;
height:100%;
left:350px;
position:absolute;
top:0;
bottom:0;
right:0;
}