Another Simple CSS3 Dropdown Menu

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/font-awesome/3.2.0/css/font-awesome.min.css">
<ul>
  <li><i class="icon-home"></i> Home</li>
  <li><i class="icon-question"></i> About</li>
  <li><i class="icon-cog"></i> Portfolio
    <ul>
      <li><i class="icon-pencil"></i> Web Design</li>
      <li><i class="icon-pencil"></i> Web Development</li>
      <li><i class="icon-pencil"></i> Illustrations</li>
    </ul>
  </li>
  <li><i class="icon-edit"></i> Blog</li>
  <li><i class="icon-envelope"></i> Contact</li>
</ul>

CSS

@import url(http://fonts.googleapis.com/css?family=Raleway);
body {
  font-family: 'Raleway', sans-serif;
  padding: 20px 50px 150px;
  font-size: 13px;
  text-align: center;
  background: #f0f0f0;
}

ul {
  text-align: left;
  display: inline;
  margin: 0;
  padding: 15px 4px 17px 0;
  list-style: none;
  -webkit-box-shadow: 0 0 5px rgba(0, 0, 0, 0.25);
  -moz-box-shadow: 0 0 5px rgba(0, 0, 0, 0.25);
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.25);
}
ul li {
  font: 13px/18px 'Raleway';
  display: inline-block;
  margin-right: -4px;
  position: relative;
  padding: 15px 20px;
  background: #fff;
  cursor: pointer;
  -webkit-transition: all 0.2s;
  -moz-transition: all 0.2s;
  -ms-transition: all 0.2s;
  -o-transition: all 0.2s;
  transition: all 0.2s;
}
ul li i { margin-right: 4px; }
ul li:hover {
  background: #555;
  color: #fff;
}
ul li ul {
  padding: 0;
  position: absolute;
  top: 48px;
  left: 0;
  width: 200px;
  -webkit-box-shadow: none;
  -moz-box-shadow: none;
  box-shadow: none;
  display: none;
  opacity: 0;
  visibility: hidden;
  -webkit-transiton: opacity 0.2s;
  -moz-transition: opacity 0.2s;
  -ms-transition: opacity 0.2s;
  -o-transition: opacity 0.2s;
  -transition: opacity 0.2s;
}
ul li ul li { 
  background: #555; 
  display: block; 
  color: #fff;
  text-shadow: 0 -1px 0 #000;
}
ul li ul li:hover { background: #666; }
ul li:hover ul {
  display: block;
  opacity: 1;
  visibility: visible;
}