如何使用HTML和CSS修复导航栏burger

<nav>
  <ul>
    <li><a href="#">Home</a></li>
    <li><a href="#">About</a></li>
    <li><a href="#">Services</a></li>
    <li><a href="#">Contact</a></li>
    <li class="burger"><a href="#"><span></span></a></li>
  </ul>
</nav>

nav {
  background-color: #333;
  padding: 10px;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

nav ul li {
  display: inline-block;
  margin-right: 10px;
}

nav ul li a {
  color: #fff;
  text-decoration: none;
}

nav ul li.burger {
  display: none;
}

@media screen and (max-width: 768px) {
  nav ul li:not(.burger) {
    display: none;
  }

  nav ul li.burger {
    display: inline-block;
  }

  nav ul li.burger a span {
    display: block;
    width: 30px;
    height: 3px;
    background-color: #fff;
    margin-bottom: 5px;
  }

  nav ul li.burger a:hover span {
    background-color: #ccc;
  }

  nav ul li.burger.active a span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }

  nav ul li.burger.active a span:nth-child(2) {
    opacity: 0;
  }

  nav ul li.burger.active a span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
  }

  nav ul li.burger.active ~ li {
    display: block;
  }
}

document.querySelector('.burger').addEventListener('click', function() {
  this.classList.toggle('active');
});