#contents_left .content p.customlink {
  background: #efefef; 
  padding: 20px; 
  margin-bottom: 50px; 
  margin-top: -20px;
  font-size: 18px;
  font-weight: bold;
}
#contents_left .content p.customlink span {
  font-size:16px;
  font-weight: normal;
}

@media screen and (max-width : 768px){
  #contents_left .content p.customlink {
    font-size: 16px;
  }
  #contents_left .content p.customlink span {
    font-size:14px;
  }
}