Here is a nice example http://codepen.io/nikhil/pen/qcyGF
Detailed tutorial at http://thecodeblock.com/realistic-soft-search-box-in-pure-css/
Here is a nice example http://codepen.io/nikhil/pen/qcyGF
Detailed tutorial at http://thecodeblock.com/realistic-soft-search-box-in-pure-css/