在HTML中展开居中导航栏

<nav>
  <ul>
    <li><a href="#">首页</a></li>
    <li><a href="#">产品</a></li>
    <li><a href="#">服务</a></li>
    <li><a href="#">关于我们</a></li>
    <li><a href="#">联系我们</a></li>
  </ul>
</nav>

nav {
  display: flex;
  justify-content: center;
}

ul {
  display: flex;
  list-style-type: none;
  padding: 0;
}

li {
  margin: 0 10px;
}

a {
  text-decoration: none;
  color: #333;
}

nav {
  display: flex;
  justify-content: center;
}

ul {
  display: none;
  list-style-type: none;
  padding: 0;
}

li {
  margin: 0 10px;
}

a {
  text-decoration: none;
  color: #333;
}

nav:hover ul {
  display: flex;
  flex-direction: column;
  align-items: center;
}