/* #margemBottom { height:25px; width:100%; bottom:0; left:0; z-index:4; background: #fff; } */
#margemBottom { 
    background: #fff none repeat scroll 0 0;
    bottom: 0;
    max-height: 250px;
    left: 0;
    position: fixed;
    width: 100%;
    z-index: 1001;
}