.nav-link:visited,
.nav-link:link {
  border-bottom: 1px solid transparent;
}

.nav-link:hover,
.nav-link:active {
  border-bottom: 1px solid #fff;
}

.nav.navbar-nav li a {
     color: #fff !important; 
 }
 .nav .navbar-nav li a:hover { 
     color: white !important;
 }