@media screen and (max-width: 767.999px) {
  #subpage_title_area h1 {
    font-size: 24px;
  }
  section.first_section {
    padding: 50px 30px;
  }
  section.first_section section.contents {
    margin: 35px auto 0;
  }
  section.first_section section.contents:nth-of-type(1) {
    margin-top: 0;
  }
  section.first_section section.contents h2 {
    font-size: 16px;
  }
  section.first_section section.contents .txt {
    margin-top: 10px;
    line-height: 2;
  }
}