@media only screen and (max-width: 800px) {

  body #logo, body #logo img
  {
       margin-top: 5px !important;
    margin-bottom: 15px !important;
    margin-left: 0px !important;
     margin-right: 0px !important; 
  }
  body .form_don_visiteur , body .form_don_visiteur_content
  {
   width:100% !important;
  }
   body .form_don_visiteur h2
  {
       font-size: 20px;
  }
  body .form_don_visiteur input[type="submit"].Btn {
   padding: 10px 10px !important;
   display: block;
    width: 100%;
    font-size: 15px;
  }
  body #logo
  {
    max-width: 100% !important;
    text-align:center;
  }
}