<nav><span class="text">NEXT</span>
  <div class="left">
    <a href="" class="prev"></a>
    <a href="">1</a>
    <a href="">2</a>
    <a href="">3</a>
    <span class="line"></span>
  </div>
  <div class="right">
    <a href="" class="next"></a>
    <a href="">4</a>
    <a href="">5</a>
    <a href="">6</a>
    <span class="line"></span>
   </div>
</nav>

body {
  margin: 0;
  background: #F6B533;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  font-family: "Lucida Sans Unicode", "Lucida Grande", Sans-Serif;
}
a {
  text-decoration: none;
  outline: none;
  display: block;
  padding: 20px 0;
  width: 40px;
  text-align: center;
  color: white;
  float: left;
}
div {
  position: absolute;
  top: 0;
  opacity: 0;
  width: 40px;
  overflow: hidden;
  transition: .5s linear;
}
.left {
  left: 0;
}
.right {
  right: 0;
}
.line {
  width: 30px;
  height: 2px;
  position: absolute;
  bottom: 10px;
  left: -35px;
  background: white;
  transition: .5s linear .2s;  
}
.left a:nth-child(2):hover ~ .line,
.right a:nth-child(2):hover ~ .line {
  left: 5px; 
}
.left a:nth-child(3):hover ~ .line,
.right a:nth-child(3):hover ~ .line {
  left: 45px; 
}
.left a:nth-child(4):hover ~ .line, 
.right a:nth-child(4):hover ~ .line {
  left: 85px; 
}
nav {
  background: #FCFCFC;
  color: #4D4644;
  position: relative;
  border-radius: 6px;
  overflow: hidden;
  width: 600px;
  text-align: center;
  box-shadow: 0 0 20px rgba(0,0,0,.2);
  transition: .3s linear;
}
.text {
  display: inline-block;
  letter-spacing: 2px;
  padding: 20px 10px;
  cursor: pointer;
}
nav:hover div {
  background: #D8CDC9;
  opacity: 1;
}
div:hover .prev {
  opacity: 0;
  display: none;
}
div:hover .next {
  display: none;
}
div:hover {
  width: auto;
}
.prev:before {
  content: "\f104";
  font-family: FontAwesome;
}
.next:before {
  content: "\f105";
  font-family: FontAwesome;
}