Pure CSS Mobile-compatible Responsive Dropdown Menu

A pure CSS responsive menu created by andornagy that automatically changes to a toggleable dropdown menu at a specified breakpoint based on CSS3 media queries.

How to use it:

Create a regular multi-level navigation menu using nested unordered list. It uses checkbox & label technique to toggle sub menus.

<nav>
  <div id="logo">Your Logo here</div>
  <label for="drop" class="toggle">Menu</label>
  <input type="checkbox" id="drop" />
  <ul class="menu">
    <li><a href="#">Home</a></li>
    <li> 
      <!-- First Tier Drop Down -->
      <label for="drop-1" class="toggle">Service +</label>
      <a href="#">Service</a>
      <input type="checkbox" id="drop-1"/>
      <ul>
        <li><a href="#">Service 1</a></li>
        <li><a href="#">Service 2</a></li>
        <li><a href="#">Service 3</a></li>
      </ul>
    </li>
    <li> 
      
      <!-- First Tier Drop Down -->
      <label for="drop-2" class="toggle">Portfolio +</label>
      <a href="#">Portfolio</a>
      <input type="checkbox" id="drop-2"/>
      <ul>
        <li><a href="#">Portfolio 1</a></li>
        <li><a href="#">Portfolio 2</a></li>
        <li> 
          
          <!-- Second Tier Drop Down -->
          <label for="drop-3" class="toggle">Works +</label>
          <a href="#">Works</a>
          <input type="checkbox" id="drop-3"/>
          <ul>
            <li><a href="#">HTML/CSS</a></li>
            <li><a href="#">jQuery</a></li>
            <li><a href="#">Python</a></li>
          </ul>
        </li>
      </ul>
    </li>
    <li><a href="#">Blog</a></li>
    <li><a href="#">Submit</a></li>
    <li><a href="#">Contact</a></li>
    <li><a href="#">About</a></li>
  </ul>
</nav>

The core CSS styles for the navigation menu.

nav {
  margin: 0;
  padding: 0;
  background-color: #254441;
}
#logo {
  display: block;
  padding: 0 30px;
  float: left;
  font-size: 20px;
  line-height: 60px;
}
nav:after {
  content: "";
  display: table;
  clear: both;
}
nav ul {
  float: right;
  padding: 0;
  margin: 0;
  list-style: none;
  position: relative;
}
nav ul li {
  margin: 0px;
  display: inline-block;
  float: left;
  background-color: #254441;
}
nav a {
  display: block;
  padding: 0 20px;
  color: #FFF;
  font-size: 20px;
  line-height: 60px;
  text-decoration: none;
}
nav ul li ul li:hover { background: #000000; }
nav a:hover { background-color: #000000; }
nav ul ul {
  display: none;
  position: absolute;
  top: 60px;
}
nav ul li:hover > ul { display: inherit; }
nav ul ul li {
  width: 170px;
  float: none;
  display: list-item;
  position: relative;
}
nav ul ul ul li {
  position: relative;
  top: -60px;
  left: 170px;
}
li > a:after { content: ' +'; }

.toggle, [id^=drop] {
 display: none;
}

li > a:only-child:after { content: ''; }

The CSS3 media queries to define how the navigation menu works on mobile devices (screen size < 768px).

@media all and (max-width : 768px) {
#logo {
  display: block;
  padding: 0;
  width: 100%;
  text-align: center;
  float: none;
}
nav { margin: 0; }
.toggle + a,
 .menu { display: none; }
.toggle {
  display: block;
  background-color: #254441;
  padding: 0 20px;
  color: #FFF;
  font-size: 20px;
  line-height: 60px;
  text-decoration: none;
  border: none;
}
.toggle:hover { background-color: #000000; }
[id^=drop]:checked + ul { display: block; }
nav ul li {
  display: block;
  width: 100%;
}
nav ul ul .toggle,
 nav ul ul a { padding: 0 40px; }
nav ul ul ul a { padding: 0 80px; }
nav a:hover,
 nav ul ul ul a { background-color: #000000; }
nav ul li ul li .toggle,
 nav ul ul a { background-color: #212121; }
nav ul ul {
  float: none;
  position: static;
  color: #ffffff;
}
nav ul ul li:hover > ul,
nav ul li:hover > ul { display: none; }
nav ul ul li {
  display: block;
  width: 100%;
}
nav ul ul ul li { position: static;
}
}
@media all and (max-width : 330px) {
nav ul li {
  display: block;
  width: 94%;
}
}