.menu-toggle{
  display:none;
  font-size:26px;
  cursor:pointer;
}

@media(max-width:768px){
  nav{
    position:absolute;
    top:65px;
    left:0;
    width:100%;
    background:#fff;
    flex-direction:column;
    box-shadow:0 4px 10px rgba(0,0,0,.1);
    display:none;
  }

  nav a{
    margin:15px;
    display:block;
    text-align:center;
  }

  nav.active{
    display:block;
  }

  .menu-toggle{
    display:block;
  }
}