.container-navbar-grey ul {
  background: #003f14;
  list-style: none;
  padding: 0;
  margin: 0;
  overflow: hidden;
  height: 40px;
}
.container-navbar-grey ul li {
  color: white;
  text-align: center;
  height: 0;
  line-height: 40px;
  opacity: 0;
  transition: opacity 0.5s;
}
.container-navbar-grey ul li.active {
  height: auto;
  opacity: 1;
}