Below you’ll find an approach to nav items I cooked up where they are initially blurred and come into focus on hover. Bonus is the changing gradient border.

Here is the HTML:

  

	<header class="site-header" role="banner">
	  <div class="wrapper">
	    <a class="site-title" href="/">Site Name</a>
	      <nav class="site-nav">
	        <input type="checkbox" id="nav-trigger" class="nav-trigger">
	        <label for="nav-trigger">
	          <span class="menu-icon">
	            <svg viewBox="0 0 18 15" width="18px" height="15px">
	              <path fill="#424242" d="M18,1.484c0,0.82-0.665,1.484-1.484,1.484H1.484C0.665,2.969,0,2.304,0,1.484l0,0C0,0.665,0.665,0,1.484,0 h15.031C17.335,0,18,0.665,18,1.484L18,1.484z"></path>
	              <path fill="#424242" d="M18,7.516C18,8.335,17.335,9,16.516,9H1.484C0.665,9,0,8.335,0,7.516l0,0c0-0.82,0.665-1.484,1.484-1.484 h15.031C17.335,6.031,18,6.696,18,7.516L18,7.516z"></path>
	              <path fill="#424242" d="M18,13.516C18,14.335,17.335,15,16.516,15H1.484C0.665,15,0,14.335,0,13.516l0,0 c0-0.82,0.665-1.484,1.484-1.484h15.031C17.335,12.031,18,12.696,18,13.516L18,13.516z"></path>
	            </svg>
	          </span>
	        </label>
	        <div class="trigger">
	              <a class="page-link" href="/item-1/">
	                item 1
	              </a>
	              <a class="page-link" href="/item-2/">
	                item 2
	              </a>
	              <a class="page-link" href="/item-3/">
	                item 3
	              </a>
	        </div>
	      </nav>
	  </div>

	</header>

And here is the CSS:

	
		.site-header {
		  background-color: white;
		  border-top: 0;
		  color: transparent;
		  overflow: hidden;
		  position: relative;
		  text-decoration: none;
		  vertical-align: bottom;
		  z-index: 2;
		  text-shadow: 0px 0px 3px rgba(122, 95, 255, 0.75);
		}
		.site-header:after {
		  content: "";
		  height: 3px;
		  left: 0;
		  position: absolute;
		  bottom: 0;
		  width: 400%;
		  will-change: transform;
		  z-index: 1;
		  animation: underline-gradient 6s linear infinite;
		  background-image: linear-gradient(90deg, rgba(122, 95, 255, 0.8) 15%, rgba(1, 255, 137, 0.6) 35%, rgba(122, 95, 255, 0.8) 85%);
		}
		.site-header .site-title {
		  font-size: 25px;
		  font-weight: 100;
		  color: #3eafc4;
		  text-shadow: none;
		  text-decoration: none;
		}
		.site-header .trigger .page-link {
		  font-size: 18px;
		  font-weight: 900;
		  text-transform: uppercase;
		  padding: 5px;
		  -webkit-box-sizing: border-box;
		  -moz-box-sizing: border-box;
		  -ms-box-sizing: border-box;
		  box-sizing: border-box;
		  color: transparent;
		  text-decoration: none;
		  z-index: 2;
		  -webkit-transition: text-shadow 0.5s, color 0.5s;
		  transition: text-shadow 0.5s, color 0.5s;
		}
		.site-header .trigger .page-link:hover, .site-header .trigger .page-link:active {
		  text-shadow: none;
		  color: #3eafc4;
		  -webkit-transition: text-shadow 0.5s, color 0.5s;
		  transition: text-shadow 0.5s, color 0.5s;
		}
		.site-header .trigger .page-link.active {
		  text-shadow: none;
		  color: #3eafc4;
		}