.topnav {
  overflow: hidden;
  background-color: #b3d9ff; //#0055ee;
//  z-index:3;
  width:100%;
}

.topnav button {
  background-color: inherit;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 1px 10px 1px 10px;
  transition: 0.3s;
  font-weight:bold;
  font-size: 14px;
}

.topnav button:hover {
  background-color: #df6c20;
}

.topnav button.active {
  background-color: #df6c20;
}


.topnav .icon {
  display: none;
}


@media screen and (max-width: 600px) {
  .topnav  button {
    display: none;
  }
  .topnav a.icon {
    float: right;
    display: block;
  }
}

@media screen and (max-width: 600px) {
  .topnav.responsive {position: relative;}
  .topnav.responsive .icon {
    position: absolute;
    right: 0;
    top: 0;
  }

  .topnav.responsive a {
    float: none;
    display: block;
    text-align: left;
  }
  .topnav.responsive button {width:100%;display:block;text-align:left;}
}
/*
<script>
function myFunction() {
  var x = document.getElementById("myTopnav");
  if (x.className === "topnav") {
    x.className += " responsive";
  } else {
    x.className = "topnav";
  }
}
</script>
*/