gistfile1.txt

.nav {
  overflow: hidden;

}

.nav .menu-item {
  float: left;
  display: block;
  color: #f2f2f2;
  text-align: center;

  text-decoration: none;

}

.nav .icon {
  display: none;
}

@media screen and (max-width: 600px) {
  .nav .menu-item:not(:first-child) {display: none;}
  .nav a.icon {
    float: right;
    display: block;
  }
}

@media screen and (max-width: 600px) {
  .nav.responsive {position: relative;}
  .nav.responsive .icon {
    position: absolute;
    right: 0;
    top: 0;
  }
  .nav.responsive .menu-item {
    float: none;
    display: block;
    text-align: left;
  }
}

gistfile2.txt

<a href="javascript:void(0);" class="icon" onclick="navToggle()">
    <i class="fa fa-bars"></i>
  </a>