body, html {
  margin: 0;
  padding: 0;
}
ul#pestanas {
  list-style: none;
  margin: 0;
  padding: 3px 0 0 0;
  height: 5px;
  border-bottom: 1px solid black;
  background: rgb(222, 222, 222);
}
ul#pestanas li {
  float: left;
  margin: 0 4px;
  height: 3px;
  text-align: left;
  position: relative;
  width: 75%;
  border: 1px solid black;
  top: 1px;
  background: rgb(128, 128, 128);
}
ul#pestanas li:hover {
  border-bottom: 1px solid white;
  background: white;
}
ul#pestanas a {
  display: block;
  height: 100%;
  text-decoration: none;
  color: white;
  font: 14px Arial, sans-serif;
}

ul#pestanas span {
  display: block;
  padding: 4px 10px 0 10px;
}