body {
  font-family: sans-serif;
}

.content {
  margin-left: 18%;
  padding: 10px 46px 5px 16px;
  min-height: 500px;
  height: auto; /*1000px*/
  text-align: justify;
}

ul.sidenav {
  list-style: none;
  margin: 0;
  padding: 0;
  width: 18%;
  position: absolute;
  overflow: auto;
  height: auto;
  background-color: #ffffff;  /*#f1f1f1*/

}

ul.sidenav li a {
  display: block;
  padding: 8px 16px;
  text-decoration: none;
  color: #000;
}

ul.sidenav li a.active {
  background-color: #4CAF50;
  color: white;
}

ul.sidenav li a:hover:not(.active) {
  background-color: #00004d;   /*#111*/
  color: white;
}

@media screen and (max-width: 900px) {
  ul.sidenav {
    width: 100%;
    height: auto;
    position: relative;
  }
  ul.sidenav li a {
    float: left;
    padding: 15px;
  }
  .content {margin-left: 0;}
}

@media screen and (max-width: 400px) {
  ul.sidenav li a {
    text-align: center;
    float: none;
  }
}