anchor.diff:  <!DOCTYPE html>
   <html>
  -<head><meta content="text/html; charset=UTF-8" http-equiv="Content-Type"></head>
  +<head>
  +  <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
  +  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.css">
  +</head>
   <body>
     <table style="background-color: #eeeeee; height: 300px; padding-bottom: 40px; border:0; font-family: Helvetica,Arial,sans-serif;" cellpadding="0" cellspacing="0" width="100%">
       <tbody>
  
positive.code:                     <p style="text-align: center;margin-bottom: 20px;">
                        <%= t('contest_page.help_center.text') %>
                      </p>
                      <iframe width="720" height="405" src="https://www.youtube.com/embed/?listType=playlist&list=PL-qNzC6Q_XM5tMM04Abi8Oy-qHVovu_-0" frameborder="0" allowfullscreen></iframe>
  
                    </div>
                  </td>
                </tr>
  
negative.code:                       <a href="https://es-es.facebook.com/EducaInternet/" class="fa fa-facebook" style="color: #3b579d; margin-right: 40px;"></a>
                        <a href="https://twitter.com/EducaInternet" class="fa fa-twitter" style="margin-right: 40px; color: #1da1f3;"></a>
                        <a href="https://www.youtube.com/channel/UCH_RLT0J0CPBbOnibBO_mzg" class="fa fa-youtube-play" style="color: #d40c1d; margin-right: 40px;"></a>
                        <a href="https://blog.educainternet.es/"><img style="width: 100px; padding-top: 10px;" src="<%=Vish::Application.config.full_domain%>/assets/orange/logo-blog_educa.png"></a>
                      </div>
                      <p style="text-align: center; margin-bottom: 20px; padding-bottom: 30px;"><%= t('contest.first_mail.body6') %></p>
                    </div>
  