Edit in JSFiddle

<nav id='rolling-nav'>
    <ul>
        <li><a href='URL' data-clone='Home'>Home</a></li>
        <li><a href='URL' data-clone='Sobre'>Sobre</a></li>
        <li><a href='URL' data-clone='Portfolio'>Portfolio</a></li>
        <li><a href='URL' data-clone='Comentários'>Comentários</a></li>
        <li><a href='URL' data-clone='Contato'>Contato</a></li>
    </ul>
</nav>

body {
  background-color:#111;
  margin:0px 0px;
  padding:50px;    
}

#rolling-nav {
  font:normal 12px 'Trebuchet MS',Arial,Sans-Serif;
  color:white;
  text-transform:uppercase;    
}

#rolling-nav ul {
  height:50px;
  margin:0px 0px;
  padding:0px 0px;
  overflow:hidden;    
}

#rolling-nav li {
  float:left;
  display:inline;
  list-style:none;
  margin:0px 0px;
  padding:0px 0px;    
}

#rolling-nav a,
#rolling-nav a:before {
  display:block;
  margin:0px 0px;
  padding:0px 30px;
  line-height:50px;
  color:white;
  text-decoration:none;
  background-color:#900;
  background-image:-webkit-linear-gradient(top, #900 0%, #6A0808 50%, #620303 50%, #6A0808 100%);
  background-image:-moz-linear-gradient(top, #900 0%, #6A0808 50%, #620303 50%, #6A0808 100%);
  background-image:-ms-linear-gradient(top, #900 0%, #6A0808 50%, #620303 50%, #6A0808 100%);
  background-image:-o-linear-gradient(top, #900 0%, #6A0808 50%, #620303 50%, #6A0808 100%);
  background-image:linear-gradient(top, #900 0%, #6A0808 50%, #620303 50%, #6A0808 100%);
  -webkit-box-shadow:inset 0px 1px 0px rgba(255,255,255,0.1);
  -moz-box-shadow:inset 0px 1px 0px rgba(255,255,255,0.1);
  box-shadow:inset 0px 1px 0px rgba(255,255,255,0.1);
  position:relative;
  -webkit-transition:all 0.3s ease-in-out;
  -moz-transition:all 0.3s ease-in-out;
  -ms-transition:all 0.3s ease-in-out;
  -o-transition:all 0.3s ease-in-out;
  transition:all 0.3s ease-in-out;
}

#rolling-nav a:before {
  content:attr(data-clone);
  position:absolute;
  top:100%;
  left:0px;
  display:block;
  background-color:white;
  background-image:-webkit-linear-gradient(top, #ddd, white);
  background-image:-moz-linear-gradient(top, #ddd, white);
  background-image:-ms-linear-gradient(top, #ddd, white);
  background-image:-o-linear-gradient(top, #ddd, white);
  background-image:linear-gradient(top, #ddd, white);
  border-top:2px solid rgba(0,0,0,0.2);
  color:#333;    
}

#rolling-nav a:hover {
  margin-top:-50px;
  margin-bottom:1px;
}