奇怪的字体 – 令人敬畏的CSS下划线

当我将font-awesome的图标(当它们堆叠在一起时)悬停在下面时(见图).我得到了这些奇怪的下划线.知道他们可以来自哪里？

资源：

<div class="text-center">
          <!-- FB -->
          <a href="http://www.facebook.com/share.php?u=${shareURL}"
             target="_blank" style="color : #555">
            <i id="facebook" class="fa-3x fa fa-facebook-square"></i>
          </a>
          <!-- Twitter -->
          <a href="http://twitter.com/?status=Sign-Up+for+SolidTranslate+here!:+${shareURL}+@SolidTranslate" target="_blank" style="color : #555">
            <i id="twitter" class="fa-3x fa fa-twitter-square"></i>
          </a>
        <!-- LinkedIn -->
        <a href="http://www.linkedin.com/shareArticle?url=${shareURL}&title=Sign-Up%20for%20SolidTranslate%20here:%20${shareURL}&sumMary=To%20get%20started%20translaTing%20SolidWorks%20files%20register%2\
0here:%20${shareURL}&source=${shareURL}" target="_blank" style="color : #555">
          <i id="linkedin" class="fa-3x fa fa-linkedin-square"></i>
        </a>
        <!-- Google+ -->
        <a href="https://plus.google.com/share?url=${shareURL}"
           target="_blank"
           style="color : #555">
          <i id="googleplus" class="fa-3x fa fa-google-plus-square"></i>
        </a>

a.social { /* or whatever your class */
   text-decoration: none;
}