.cssnav {
position: relative;
font-family: arial, helvetica, sans-serif;
background-image: url(http://hyperbaric-oxygen-ca.com/image-files/overbtn.gif);
background-repeat: no-repeat;
white-space: nowrap;
display: block;
width: 160px;
height: 35px;
margin: 0;
padding: 0;
}

.cssnav a {
display: block;
font-size: 12px;
width: 160px;
height: 35px;
display: block;
float: left;
color: white;
text-decoration:none;
font-weight:bold;
}

.cssnav img {width: 160px; height: 35px; border: 0; }
* html a:hover {visibility:visible}
.cssnav a:hover img{visibility:hidden}

.cssnav span {
position: absolute;
left: 15px;
top: 10px;
margin: 0px;
padding: 0px;
cursor: pointer;
}