.menu-container {
  background-color: lightgrey;
  max-width:900px;
  margin: 0 auto;
  box-sizing: border-box;
}

.topnav {
  overflow: hidden;
  margin:auto; 
  box-sizing: border-box;
} 
  
.topnav a {
  float: left;
  display: block;
  color: black;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-size: 20px;
}

.topnav .icon {
  display: none;
}
.topnav a:not(.logo):hover {
  background-color: #00ff00;
  color: white;
}
@media screen and (max-width: 900px) {
  .topnav a:not(:first-child) {
    display: none;
  }
  .topnav a.icon {
    float: right;
    display: block;
  }
}
@media screen and (max-width: 900px) {
  .topnav.responsive {position: relative;}
  .topnav.responsive .icon {
    position: absolute;
    right: 0;
    top: 0;
  }
  .topnav.responsive a {
    float: none;
    display: block;
    text-align: left;
  } 
}