Origem: Wikipédia, a enciclopédia livre.
.menu {
list-style:none;
border:1px solid #c0c0c0;
float:left;
}
.menu li {
white-space: nowrap;
background: #575859;
border: 1px solid #464748;
border-radius: 1px;
padding: 3px 3px;
display: inline-block;
margin: 3px;
cursor: pointer;
font-size: 100%;
line-height: 1.42857143em;
color: #FFFFFF;
opacity: 1;
font-weight: bold;
}
.menu li a:hover {
background: #7B7B7D;
border: 1px solid #464748;
color: #FFFFFF;
opacity: 1;
border-radius: 1px;
padding: 3px 3px;
display: inline-block;
transition: 0.3s;
}