.mainmenu{
font-family:Arial;
font-size:12px;
font-weight:bold;
width: 100%;
}

.mainmenu ul{
padding: 6px 0 7px 0; /*6px should equal top padding of "ul li a" below, 7px should equal bottom padding + bottom border of "ul li a" below*/
margin: 0;
text-align: center; //set value to "left", "center", or "right"*/
}

.mainmenu ul li{
display: inline;
}

.mainmenu ul li a{
color: #ffffff;
padding: 6px 3px 4px 3px; /*top padding is 6px, bottom padding is 4px*/
margin-right: 10px; /*spacing between each menu link*/
text-decoration: none;
}

.mainmenu ul li a:hover{ 
color: #ffffff;
border-bottom: 2px solid #ffffff;
}