JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
 <html>

   <head>
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-    awesome/4.7.0/css/font-awesome.min.css">
   </head>

   <body>
     <div class="header">
       <h2>Scroll Down</h2>
       <p>Scroll down to see the sticky effect.</p>
     </div>

     <div class="topnav" id="myTopnav">
       <a href="#home" class="active">Home</a>
       <a href="#news">News</a>
       <a href="#contact">Contact</a>
       <div class="dropdown">
         <button class="dropbtn">Dropdown
           <i class="fa fa-caret-down"></i>
         </button>
         <div class="dropdown-content">
           <a href="#">Link 1</a>
           <a href="#">Link 2</a>
           <a href="#">Link 3</a>
         </div>
       </div>
       <a href="#about">About</a>
       <a href="javascript:void(0);" style="font-size:15px;" class="icon" onclick="myFunction()">&#9776;</a>
     </div>

     <div style="padding-left:16px">
       <h2>Responsive Topnav with Dropdown</h2>
       <p>Resize the browser window to see how it works.</p>
       <p>Hover over the dropdown button to open the dropdown menu.</p>
     </div>

     <h3>Sticky Navigation Bar Example</h3>
     <p>The navbar will <strong>stick</strong> to the top when you reach its scroll position.</p>
     <p><strong>Note:</strong> Internet Explorer do not support sticky positioning and Safari requires a -webkit- prefix.</p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to enable scrolling. </p>
     <p>Some text to...

CSS

body {
      margin: 0;
      font-family: sans-Serif;
      position: relative;
      
    }

    .topnav {
      /* overflow: hidden; */
      background-color: #333;
      position: sticky;
      top: 0;
      min-height: 48px;
    }

    .topnav a {
      list-style-type: none;
      float: left;
      display: block;
      color: #f2f2f2;
      text-align: center;
      padding: 14px 16px;
      text-decoration: none;
      font-size: 17px;
    }



    .active {
      background-color: #04AA6D;
      color: white;
    }

    .topnav .icon {
      display: none;
    }

    .dropdown {
      float: left;
    }

    .dropdown .dropbtn {
      font-size: 17px;
      border: none;
      outline: none;
      color: white;
      padding: 14px 16px;
      background-color: inherit;
      font-family: inherit;
      margin: 0;
    }

    .dropdown-content {
      display: none;
      position: absolute;
      background-color: #f9f9f9;
      min-width: 160px;
      box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.2);
      z-index: 10000000;
    }

    .dropdown-content a {
      float: none;
      color: black;
      padding: 12px 16px;
      text-decoration: none;
      display: block;
      text-align: left;
    }

    .topnav a:hover,
    .dropdown:hover .dropbtn {
      background-color: #555;
      color: white;
    }

    .dropdown-content a:hover {
      background-color: #ddd;
      color: black;
    }

    .dropdown:hover .dropdown-content {
      display: block;
    }

    @media screen and (max-width: 600px) {

      .topnav a:not(:first-child),
      .dropdown .dropbtn {
        display: none;
      }

      .topnav a.icon {
        float: right;
        display: block;
      }
    }

    @media screen and (max-width: 600px) {
      .topnav.responsive {
        position: relative;
      }

      .topnav.responsive .icon {
        position: absolute;
        right: 0;
        top: 0;
      }

      .topnav.responsive a {
        float: none;
        display:...

JavaScript

function myFunction() {
  var x = document.getElementById("myTopnav");
  if (x.className === "topnav") {
    x.className += " responsive";
  } else {
    x.className = "topnav";
  }
}