.boton {position:relative;float:right;margin-right:10px;border-color:#FFFFFF;border-width:.2em;border-style:solid;padding: 3px 10px 3px 10px;font-family: Tahoma; font-size: 13px; font-weight: bold; color: #FFFFFF;text-align:center;height:30px;vertical-align:middle;display:table-cell;}
.boton_background {position:absolute;top:0;left:0;width:100%;height:100%;background-color:#FFFFFF; opacity:0;}
.boton_background:hover {opacity:0.5;}

.boton_contenedor{position:relative;height:60px;width:761px;}