@media screen and (max-width: 1199px) {
  html {
    font-size: 15px;
  }

  #logo {
    height: 65%;
  }

  nav > ul > li {
    margin-left: 3rem;
  }
}

@media screen and (max-width: 1059px) {
  .scroll_off {
    overflow: hidden;
  }

  nav {
    display: none;
  }

  #hamburger_menu {
    display: block;
  }

  #menu_btn {
    cursor: pointer;

    position: fixed;
    top: 1.5rem;
    right: calc(2rem - calc(100vw - 100%));
    height: 3.5rem;
    width: 3.5rem;
    border-radius: 50%;
    border: solid 1px var(--border-color);
    background-color: #ffffff;

    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
  }

  #menu_btn span,
  #menu_btn span:before,
  #menu_btn span:after {
    content: "";
    display: block;
    height: 1px;
    width: 1.5rem;
    background-color: var(--border-color);
    position: absolute;
  }

  #menu_btn span:before {
    bottom: 0.5rem;
  }

  #menu_btn span:after {
    top: 0.5rem;
  }

  #menu_btn_check:checked ~ #menu_btn {
    right: 2rem;
  }

  #menu_btn_check:checked ~ #menu_btn span {
    background-color: rgba(255, 255, 255, 0);
  }

  #menu_btn_check:checked ~ #menu_btn span::before {
    bottom: 0;
    transform: rotate(45deg);
  }

  #menu_btn_check:checked ~ #menu_btn span::after {
    top: 0;
    transform: rotate(-45deg);
  }

  #menu_btn_check {
    display: none;
  }

  #menu_content_container {
    display: flex;
    flex-direction: column;
  }

  #menu_content {
    width: 100%;
    min-width: 280px;
    height: 100%;
    position: fixed;
    top: 0;
    left: 100%;
    z-index: 10;
    background-color: #fff;
    padding: 10rem 5rem 5rem;

    overflow: auto;

    transition: all 0.5s;
  }

  #menu_btn_check:checked ~ #menu_content {
    left: 0;
  }

  .hamburger_links {
    font-size: 1.6rem;
    margin-bottom: 2.5rem;
  }

  .hamburger_wulinks {
    font-size: 0.9em;
    padding-left: 3.5rem;
  }

  .hamburger_wulinks li {
    margin-top: 1.2rem;
  }

  .nv_lecture {
    position: relative;
    padding-left: 1rem;
  }

  .nv_lecture:before {
    content: "";
    width: 0.3rem;
    height: 0.3rem;
    border-radius: 50%;
    background: rgba(51, 51, 51, 0.5);
    position: absolute;
    top: 50%;
    left: -1.2rem;
    transform: translateY(-50%);
  }

  .hamburger_wulinks .btn_dot:before {
    left: -1.2rem;
  }

  .hamburger_sns {
    display: flex;
    flex-direction: column;
    align-items: flex-end;

    margin-top: 2.5rem;
  }

  .hamburger_sns li {
    margin: 0 1rem;
  }

  .hamburger_sns p {
    font-size: 0.75rem;
    color: rgba(51, 51, 51, 0.5);
    margin-top: 1rem;
  }

  .hamburger_sns i {
    color: #333333;
  }

  .hamburger_sns .yt_icon:hover {
    color: #da1725;
  }

  .contact_intro {
    padding: 1rem 4rem 1rem 0;
  }

  /* ----------     sent     ---------- */
  #sent_br1 {
    display: block;
  }
}

@media screen and (max-width: 909px) {
  html {
    font-size: 14px;
  }

  /* ----------     sent     ---------- */
  #sent_br2 {
    display: block;
  }
}

@media screen and (max-width: 739px) {
  html {
    font-size: 13px;
  }

  .container {
    width: 90%;
  }

  .jpns_title {
    margin-bottom: 1rem;
  }

  #contact {
    padding: 6rem 0 3rem;
  }

  .contact_container {
    width: 80%;
    flex-direction: column;
    text-align: center;
  }

  .contact_intro {
    padding: 0 0 3rem;
  }

  #contact_br {
    display: block;
  }

  .contact_info:before {
    width: 100%;
    height: 1px;
  }

  .ci_container {
    padding: 3rem 0;
  }

  .contact_btn,
  #phone_number {
    padding-top: 2rem;
  }

  .contact_icon p {
    padding-top: 1rem;
  }

  .footer_container {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .sns_icons {
    margin-top: 2.5rem;
  }
}

@media screen and (max-width: 649px) {
  html {
    font-size: 12px;
  }

  .jpns_title {
    margin-bottom: 0;
  }

  .eng_title {
    font-size: 5.5em;
    line-height: 7rem;
  }

  /* ----------     main     ---------- */
  .contact_title {
    margin: 12rem 0 5rem;
  }

  .contact_main {
    flex-direction: column;
  }

  .sticky_box,
  form {
    width: 100%;
  }

  .contact_texts {
    margin-bottom: 6rem;
  }
}

@media screen and (max-width: 430px) {
  html {
    min-width: 280px;
  }

  .hamburger_sns {
    align-items: flex-start;
  }

  .jpns_title {
    font-size: 1.15em;
  }

  .eng_title {
    font-size: 4em;
    line-height: 4.5rem;
  }

  /* ----------     sent     ---------- */
  #sent_texts {
    width: 80%;
    margin: auto;
  }

  #sent_texts p {
    text-align: justify;
  }

  #sent_br1,
  #sent_br2,
  #sent_br3 {
    display: none;
  }
}