Pure CSS hamburger menu with fixed positioning

index.html

<ul class="menu">
  <li><a href="#!"><i class="material-icons">menu</i></a>
  <ul>
    <li>Menu</li>
    <li>item1</li>
    <li>item2</li>
    <li>item3</li>
  </ul>
  </li>
  </ul> 

pure-css-hamburger-menu-with-fixed-positioning.markdown

Pure CSS hamburger menu with fixed positioning

A Pen by Rys on CodePen.

License.

style.css

/* remove default styles, margins and any padding */
.menu, .menu * {
  margin:0;
  padding:0;
  list-style:none;
}

.menu ul {  
 display:none;
}

.menu ul li {
  padding:0.5em 0;
  border-bottom: 1px solid white;
  text-align: center;
}

.menu ul li:first-child {
  background: #ccc;
  font-weight: bold;
}

.menu > li:focus-within ul {
  display:block; 
  position:fixed;
  top:0;
  left:0;
  background: teal;
  width: 30%;
  height: 100vh;
}

styles

<link href="https://cdnjs.cloudflare.com/ajax/libs/material-design-icons/3.0.1/iconfont/material-icons.min.css" rel="stylesheet" />