.phone-btn {
  display: none; 
}

@media all and (max-width: 720px) {
  .phone-btn {
    display: block;
    position: fixed;
    bottom: 150px;
    right: 10px;
    width: 60px;
    height: 60px;
    background-image: url('/themes/repository/vizitka/images/phone-ico.png');
    background-repeat: no-repeat;
    background-position: center;
    background-size: 50px;
  }
}