nav {
  height: 40px;
  width: 100%;
  background: #003653;
  font-size: 11pt;
  font-family: 'Open Sans';
  font-weight: bold;
  position: relative;
  text-transform: uppercase;
  border-bottom: 2px solid #283744;
}
nav ul {
  float: right;
  height: 40px;
  padding: 0;
  margin: 0;
}
nav li {
  display: inline;
  float: left;
}
.clearfix:before,
.clearfix:after {
    content: " ";
    display: table;
}
.clearfix:after {
    clear: both;
}
.clearfix {
    *zoom: 1;
}
nav a {
  color: #fff;
  display: inline-block;
  width: 150px;
  text-align: center;
  text-decoration: none;
  line-height: 40px;
  text-shadow: 1px 1px 0px #283744;
}
nav li a {
  border-left: 1px solid #576979;
  box-sizing:border-box;
  -moz-box-sizing:border-box;
  -webkit-box-sizing:border-box;
}
/*nav li:last-child a {
  border-left: 0;
}*/
nav a:hover, nav a:active {
  background-color: #8c99a4;
}
nav a#pull {
  display: none;
}  
@media screen and (max-width: 600px) {
  nav { 
      height: auto;
    }
    nav ul {
      float: none;
      width: 100%;
      display: block;
      height: auto;
    }
    nav li {
      width: 50%;
      float: right;
      position: relative;
    }
    nav li a {
    border-bottom: 1px solid #576979;
    border-right: 1px solid #576979;
  }
    nav a {
      text-align: left;
      width: 100%;
      text-indent: 25px;
    }
} 

@media only screen and (max-width : 480px) {
  nav {
    border-bottom: 0;
    z-index: 10;
  }
  nav ul {
    display: none;
    height: auto;
  }
  nav a#pull {
    display: block;
    background-color: #283744;
    width: 100%;
    position: relative;
  }
  nav a#pull:after {
    content:"";
    background: url('http://ad-visors.com.ar/prueba/css/nav-icon.png') no-repeat;
    width: 30px;
    height: 30px;
    display: inline-block;
    position: absolute;
    right: 15px;
    top: 10px;
  }
}
@media only screen and (max-width : 320px) {
  nav li {
    display: block;
    float: left;
    width: 100%;
  }
  nav li a {
    border-bottom: 1px solid #576979;
  }
}