How to implement vertical accordion menu with CSS3 dark background

How to implement vertical accordion menu with CSS3 dark background: BY Terry23 Nov,2020; Tags:
CSS3 Menu Accordion Menu

Introduction

This time I want to share a vertical accordion menu with a dark background based on CSS3. The implementation principle is similar to the previous one, but the menu display form is slightly different. When the accordion menu is expanded, the sub-menu will have a horizontal fly-in animation. effect.

How to implement vertical accordion menu with CSS3 dark background

Instructions

HTML Body Code

<ul class="menu">
   <li class="list"><a href="#">List 1 </a> 
      <ul class="items">
         <li><a href="#"> Item 1-1</a></li>
         <li><a href="#"> Item 1-2</a></li>
         <li><a href="#"> Item 1-3</a></li>
      </ul>
   </li>
   <li class="list"><a href="#">List 2</a> 
      <ul class="items">
         <li> <a href="#" > Item 2-1 </a></li>
         <li> <a href="#" > Item 2-2 </a></li>
         <li> <a href="#" > Item 2-3 </a></li>
      </ul>
   </li>
   <li class="list"><a href="#">List 3</a> 
      <ul class="items">
         <li> <a href="#" > Item 3-1 </a></li>
         <li> <a href="#" > Item 3-2 </a></li>
         <li> <a href="#" > Item 3-2 </a></li>
      </ul>
   </li>
   <li class="list"><a href="#">List 4</a> 
      <ul class="items">
         <li> <a href="#" > Item 4-1 </a></li>
         <li> <a href="#" > Item 4-2 </a></li>
         <li class="list"><a href="#">List 4-1</a> 
            <ul  class="items">
               <li> <a href="#" > Item 4-1-1</a></li>
               <li> <a href="#" > Item 4-1-2</a></li>
               <li class="list"><a href="#">List 4-2</a> 
                  <ul  class="items">
                     <li> <a href="#" > Item 4-2-1</a></li>
                     <li> <a href="#" > Item 4-2-2</a></li>
                  </ul>
               </li>
            </ul>
         </li>
      </ul>
   </li>
</ul>

Css Code

body {
  padding: 0;
  margin: 0;
  background-color: #324252;
}

h1 {
  font-family: 'Century Gothic';
  margin: 30px auto 30px auto;
  color: #09fbd2;
  width: 100%;
  text-align: center;
}

ul.menu {
  padding: 0;
  list-style: none;
  width: 400px;
  margin: 20px auto;
  font-family: 'Century Gothic';
  box-shadow: 0px 0px 25px #00000070;
  clear: both;
  display: table;
}
ul.menu .list {
  font-size: 14px;
  border-bottom: 1px solid #324252;
  position: relative;
  width: 100%;
  box-sizing: border-box;
  height: 50px;
  vertical-align: sub;
  background: #3e5165;
  clear: both;
}

Js Code

var list = document.querySelectorAll('.list');

function accordion(e) {
    e.stopPropagation();
    if (this.classList.contains('active')) {
        this.classList.remove('active');
    } else
    if (this.parentElement.parentElement.classList.contains('active')) {
        this.classList.add('active');
    } else
    {
        for (i = 0; i < list.length; i++) {
            list[i].classList.remove('active');

        }
        this.classList.add('active');
    }
}
for (i = 0; i < list.length; i++) {
    list[i].addEventListener('click', accordion);
}

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