nav
{
    position: sticky!important;
    top: 0;
    opacity: .9;
    background: #ddd;
    z-index: 100;
}
nav a:hover
{
    color: black!important;
}
.nav-un
{
	display: inline-block;
} 
.nav-un::after
{
	content: '';
	width: 0px;
	height: 1px;
	display: block;
	background: black;
	transition: 200ms;
}
.nav-un:hover::after
{
	width: 100%;
}
.nav-un:hover
{
	color: white;
}