CSS 및 JavaScript를 사용하여 스크롤할 때 탐색 모음을 아래로 슬라이드하는 방법은 무엇입니까?

다음은 CSS를 사용하여 스크롤할 때 탐색 모음을 아래로 슬라이드하는 코드입니다 -

예시

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
body{
   margin:0px;
   margin-top:60px;
   padding: 0px;
}
nav{
   position: fixed;
   top: -50px;
   width: 100%;
   background-color: rgb(39, 39, 39);
   overflow: auto;
   height: auto;
   transition: 0.5s;
}
.links {
   display: inline-block;
   text-align: center;
   padding: 14px;
   color: rgb(178, 137, 253);
   text-decoration: none;
   font-size: 17px;
}
.links:hover {
   background-color: rgb(100, 100, 100);
}
.selected{
   background-color: rgb(0, 18, 43);
}
.sample-content{
   height: 150vh;
}
</style>
</head>
<body>
<nav>
<a class="links selected" href="#"> Home</a>
<a class="links" href="#"> Login</a>
<a class="links" href="#"> Register</a>
<a class="links" href="#"> Contact Us</a>
<a class="links" href="#">More Info</a>
</nav>
<div class="sample-content">
<h1>Here are some headers</h1>
<h2>Here are some headers</h2>
<h3>Here are some headers</h3>
<h4>Here are some headers</h4>
<h1>Here are some headers</h1>
<h2>Here are some headers</h2>
<h3>Here are some headers</h3>
<h4>Here are some headers</h4>
</div>
<script>
window.onscroll = scrollShowNav;
function scrollShowNav() {
   if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {
      document.getElementsByTagName("nav")[0].style.top = "0";
   } else {
      document.getElementsByTagName("nav")[0].style.top = "-50px";
   }
}
</script>
</body>
</html>