@media screen and (max-width: 900px) {
  /* header */
  .header-wrap p {
    font-size: 1.5rem;
  }

  /* nav */

  nav {
    position: fixed;
    height: 48px;
    background: transparent;
    z-index: 100;
  }

  #btn-sp-menu {
    display: block;
    height: 48px;
    position: fixed;
    width: 100%;
    background: #333333;
    z-index: 100000;
  }

  #btn-sp-menu a {
    position: absolute;
    color: #fff;
    text-decoration: none;
    line-height: 48px;
    font-size: 30px;
    text-align: center;
    padding: 0 10px;
  }

  #btn-sp-menu #logo-sp {
    height: 48px;
    width: 110px;
    left: 0;
  }

  #btn-sp-menu #logo-sp img {
    height: 44px;
    margin: 2px 0;
  }

  #btn-sp-menu a#menu-sp {
    position: absolute;
    color: #fff;
    text-decoration: none;
    line-height: 48px;
    font-size: 30px;
    text-align: center;
    padding: 0 10px;
    right: 0;
  }



  nav > ul {
    display: none;
    background-color: #333333aa;
    z-index: 100;
    display: block;
    text-align: left;
    height: 100vh;
    position: absolute;
    top: -1200px;
  }

  nav>ul>li {
    display: block;
    /* width: 15%; */
    line-height: 64px;
    border-bottom: 1px solid #fff;
  }

  li.logo {
    display: none;
  }

  /* common parts */
  .btn-to-top {
    right: 10px;
  }

  p.title {
    font-size: 8vw;
  }

  .title {
    text-align: center;
  }

  .container {
    width: 90%;
    min-width: 0px;
    margin: 50px auto;
  }

  /* service */
  .float-50pct li {
    width: 100%;
  }

  .float-50pct-ctt {
    padding: 0 5%;
    box-sizing: border-box;
  }

  #bg-img-strux {
    background-image: url("../img/bg-strux.jpg")
  }

  #bg-img-mgzn {
    background-image: url("../img/bg-mgzn.png")
  }

  #bg-img-book {
    background-image: url("../img/bg-book.jpg")
  }

  #bg-img-speakee {
    background-image: url("../img/bg-speakee.png")
  }

  #bg-img-sea {
    background-image: url(../img/bg-sea.jpg);
  }

  /* member */
  .member-intro img {
    display: block;
    margin-left: 0;
    float: none;
    margin: auto;
  }

  /* recruit */
  .wantedly-container iframe {
    width: 100%;
    margin: 10px auto;
  }

  /* access */
  .float-50pct-info {
    width: 100%;
    height: auto;
  }

  .tb-subline {
    margin: 30px auto;
    width: 90%;
  }

  /* contact */
  .form-table {
    table-layout: fixed;
  }
  .form-table input, .form-table textarea {
    width: 100%;
    width: -moz-available;
    width: -webkit-fill-available;
    width: fill-available;

  }
}