To make the menus on the website more complete and larger, we can open it by clicking a hamburger button. Menu items are placed in the middle of the page in light gray. The background of this full-screen menu is black with a bit of transparency, and the content of the website is visible under this color. When you open this menu, a button with a close icon is created, which can be closed by clicking on it. Using such menus reduces the space occupied by menus on the website.


HTML
<!-- This script got from www.devanswer.com  -->
<div class="container">
  <div id="myNav" class="overlay">
    <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
    <div class="overlay-content">
      <a href="#">About</a>
      <a href="#">Services</a>
      <a href="#">Product</a>
      <a href="#">Contact</a>
    </div>
  </div>
  <h2>Fullscreen Navigation Menu</h2>
  <p>Click on the element below to open the fullscreen overlay navigation menu.</p>
  <p>In this example, the navigation menu will slide in, from left to right:</p>
  <span style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>
</div><div id="bcl"><a style="font-size:8pt;text-decoration:none;" href="http://www.devanswer.com ">Developers Answer</a></div>
                        

CSS
body {
  font-family: 'Lato', sans-serif;
}
.container {
  width: 90%;
  max-width: 100%;
  padding: 15px;
  margin: 0 auto;
}
.overlay {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1;
  top: 0;
  left: 0;
  background-color: rgb(0,0,0);
  background-color: rgba(0,0,0, 0.9);
  overflow-x: hidden;
  transition: 0.5s;
}
.overlay-content {
  position: relative;
  top: 25%;
  width: 100%;
  text-align: center;
  margin-top: 30px;
}
.overlay a {
  padding: 8px;
  text-decoration: none;
  font-size: 36px;
  color: #818181;
  display: block;
  transition: 0.3s;
}
.overlay a:hover, .overlay a:focus {
  color: #f1f1f1;
}
.overlay .closebtn {
  position: absolute;
  top: 20px;
  right: 45px;
  font-size: 60px;
}
@media screen and (max-height: 450px) {
  .overlay a {font-size: 20px}
  .overlay .closebtn {
  font-size: 40px;
  top: 15px;
  right: 35px;
  }
}
Javascript
function openNav() {
  document.getElementById("myNav").style.width = "100%";
}
function closeNav() {
  document.getElementById("myNav").style.width = "0%";
}