css - How can i add effect hover on span in <a> -

how can add background <span> when mouse hover <span> or <a>.

<a href="" class="special"><span class="fa fa-facebook"></span> facebook</a> 

css selecting elements. here want select span when parent <a> tag hovered. use a:hover > span.

#activation:hover > #activated {    color:red;  }

<a id="activation" href="" class="special">    <span id="activated" class="fa fa-facebook">?</span>    <span>facebook</span>  </a>