div.sample01{
    position:relative;
    width:500px;
    height:190px;
}

div.sample02{
    position:relative;
    width:500px;
    height:387px;
}

div.sample03{
    position:relative;
    width:200px;
    height:155px;
}

div.sample04{
    position:relative;
    width:360px;
    height:180px;
}

span.guard{
    position:absolute;
    display:block;
    width:100%;
    height:100%;
    background-image:url(../img/spacer.gif);
}