nav {
    -webkit-user-select: none; /* Safari */        
    -moz-user-select: none; /* Firefox */
    -ms-user-select: none; /* IE10+/Edge */
    user-select: none; /* Standard */

    position: fixed;
    z-index: 9;
    top: 0;
    left: 0;
    width: 100%;
    height: 36px;

    background: black;
  }
  
  nav ul {
    list-style: none;
    margin: 0;
    padding: .2em 2em;
    float: right;
  }
  
  nav ul li {
    display: inline-block;
    margin: 0;
    padding: .2em .7em;
  }
  
  nav a {
    width: 100%;
    height: 100%;
    text-decoration: none;
    font-family: Ubuntu;
    font-size: 1.15em;
    font-weight: lighter;
    letter-spacing: 1px;
    transition: .25s ease-in-out;
  }

  .a0{
    color: #ff0100;
  }
  .a1{
    color: #FF00BB;
  }
  .a2{
    color: #8A00FF;
  }
  .a3{
    color: #001BFF;
  }

  .a0:hover{
    color: #00FEFF;
  }
  .a1:hover{
    color: #00FF44;
  }
  .a2:hover{
    color: #75FF00;
  }
  .a3:hover{
    color: #FFF800;
  }