css make navbar on top code example

Example 1: html navigation bar

<!--Method 1: Using HTML5 Nav Tag-->
<nav>
	Thing1 |
  	Thing2 |
  	Thing3
</nav>

<!--Method 2: HTML5 + CSS3 with DIV element-->

<ul class="topnav">
  <li><a class="active" href="#">Thing 1</a></li>
  <li><a href="#">Page 1</a></li>
  <li><a href="#">Page 2</a></li>
  <li class="right" ><a href="#">Thing 2</a></li>
</ul>
<style>
	
  ul.topnav {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
    font-family: arial;
    text-align: left;
    width: 100%;
    position: sticky;
    top: 0;
  }
  ul.topnav li {float: left;}
  ul.topnav li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    float: left;
    font-size: 17px;
    border-right: 1px solid #bbb;
  }
  ul.topnav li a:hover:not(.active) {
      background-color: #ddd;
      color: black;
  }
  ul.topnav li a.active {
      background-color: #4CAF50;
  }
  ul.topnav li.right {
      float: right;
  }
  @media screen and (max-width: 720px) {
    ul.topnav li{
        width: 100%;
    }
    ul.topnav a{
        width: 100%;
    }
  }
</style>

Example 2: fixed navigation menu

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  height: 1200px;
  font-size: 18px;
  font-family: sans-serif;
  color: #5D6063;
}

a:link,
a:visited {
  color: #5D6063;
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

.header {
  position: fixed;
  display: flex;
  justify-content: space-between;
  
  width: 100%;
  padding: 50px;
  background: #D6E9FE;
}