Apple-inspired search box or search field using CSS3 alone. The search field expands slowly when focused/clicked. This animation effect achieved purely using CSS3 transition property. Also, we have used other CSS3 properties such as border-radius, box-shadow and text-shadow to create cool effects.

Here is the code for the searchbox.

<form method="get" action="/search" id="search">
  <input name="q" type="text" size="40" placeholder="Search..." />
</form>

And the following are CSS codes of three different styles of the search box.

#search {

}

#search input[type="text"] {
    background: url(search-dark.png) no-repeat 10px 6px #444;
    border: 0 none;
    font: bold 12px Arial,Helvetica,Sans-serif;
    color: #777;
    width: 150px;
    padding: 6px 15px 6px 35px;
    -webkit-border-radius: 20px;
    -moz-border-radius: 20px;
    border-radius: 20px;
    text-shadow: 0 2px 2px rgba(0, 0, 0, 0.3);
    -webkit-box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.2) inset;
    -moz-box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.2) inset;
    box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.2) inset;
    -webkit-transition: all 0.7s ease 0s;
    -moz-transition: all 0.7s ease 0s;
    -o-transition: all 0.7s ease 0s;
    transition: all 0.7s ease 0s;
    }

#search input[type="text"]:focus {
    width: 200px;
    }

The article source:http://www.bloggermint.com/2011/06/css3-search-box-inspired-by-apple-com/