body {
}
.curtain_left
{
    padding: 0px;
    margin: 0px;
    width: 50px;
    height:100%;
    display: block;
    float:left;
}
.curtain_right
{
    padding: 0px;
    margin: 0px;
    width: 50px;
    height:100%;
    display: block;
    float:right;
}

.curtain_top
{
    padding: 0px;
    margin: 0px;
    width: 100%;
    height:25px;
    display: block;
}