Css NicJhe

#Master
{
 width: 800px;
 height: 600px;
 border: 1px solid #000;
}
#Master #D1
{
 width: 779px;
 height: 100px;
 border: 2px solid #f00;
 margin: 9px;
}
#Master #D2
{
 width: 150px;
 height:350px;
 border: 2px solid #00f;
 margin: 10px;
 float: left;
}
#Master #D3
{
 width: 580px;
 height: 350px;
 border: 2px solid #000;
 margin: 10px;
 float: right;
}
#Master #D4
{
 width: 779px;
 height: 80px;
 border: 2px solid #000;
 margin: 9px;
 float: right;
}