@media screen and (min-width: 769px) {
  #whole #contents #main h2 {
    font-size: 3.06vw;
  }
  #whole #contents #main sub {
    font-size: 1.73vw;
  }
}
@media screen and (max-width: 768px) {
  #whole #contents #main h2 {
    font-size: 5.33vw;
  }
  #whole #contents #main sub {
    font-size: 4vw;
  }
}
div#explanation-date {
  margin-top: 10px;
}

select.explanation {
  width: 200px;
  height: 40px;
}