Complementar la hoja de estilo

#menu li{
display: inline-block;
}

#menu a {
display: block;
float: left;
margin_right: 0.12em;
padding: 1em 1.5em;
background: #178EAE;
box-shadow: inset 0px -2px 0px 0px rgba(0,0,0,0.25);
text-decoration: none;
text-shadow: 1px 1px 0px #0C749C;
text-transform: uppercase;
font-size: .90em;
color: #FFFFFF;
}