#social_side_links {
      position: fixed;
      top: 110px;
      left: 0;
      padding: 0;
      list-style: none;
      z-index: 99;
}

#social_side_links li a {
      display: block;
}

#social_side_links li a img {
      display: block;
      max-width: 50px;
      padding: 10px;
      -webkit-transition: background .2s ease-in-out;
      -moz-transition: background .2s ease-in-out;
      -o-transition: background .2s ease-in-out;
      transition: background .2s ease-in-out;
}

#social_side_links li a:hover img {
      background: rgba(0, 0, 0, .2);
}