* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  color: #000000;
  list-style: none;
  text-decoration: none;
}

.header_bg {
  background: #ffffff;
  width: 100%;
  height: 80px;
  border-bottom: 1px solid;
  border-color: #000000;
}

.site-logo img {
  height: 50px;
  width: auto;
}

.header_contents {
  width: 100%;
  max-width: 1024px;
  height: 100%;
  margin: 10px 0 0 0;
  display: flex;
}

.header_contents h1 {
  font-size: 22px;
  margin: 0 0 0 40px;
}

.contents {
  margin-top: 100px;
  margin-right: auto;
  margin-left: auto;
  display: flex;

  padding-bottom: 60px;
  display: flex;
  justify-content: center;
}

.contents ul {
  font-family: 'Arial', 'Helvetica', 'Helvetica', sans-serif;
  font-kerning: auto;
  letter-spacing: -0.3px;
  color: #4d5156;
}


.contents ul img {
  max-width: 500px;
  margin-right: 50px;
}
.site-footer {
  background: #dddddd;
  bottom: 0;
  left: 0;
  width: 100%;
  position: absolute;
  flex-shrink: 0;
  /* フッターがコンテンツよりも小さくなるのを防ぎます */
  margin-top: auto;
}

.copyright {
  color: #292929;
  font-size: 10px;
  margin-left: 70%
}


@media screen and (max-width: 768px) {
  .responsive_btn {
    display: flex;
  }

  .header_bg {
    position: relative;
  }

  .header_nav {
    background: #ffffff;
    width: 100%;
    height: 100vh;
    padding: 80px 0 0 0;
    position: fixed;
    top: 0;
    right: -100%;
    transition: .5s;
    border-left: 1px solid;
    border-color: #000000;
  }

  .header_nav_lists {
    display: block;
    text-align: center;
  }

  .header_nav_lists li {
    margin: 0 0 40px;
    text-align: center;
  }

  .nav_link {
    color: #4a4a4a;
    font-size: 20px;
    font-family: "Impact";
    color: #0654A6;
  }

  .contents {
    margin-top: 0;
    margin-left: 30px;
    margin-right: 30px;
  }

  .contents ul {
    display: block
  }

  .contents img {
    width: 100%;
  }

  .contents ul li ul {
    display: block;
    margin-bottom: 0;
  }

  .contents ul li ul li ul {
    display: block;
    width: 100%;
  }

  .contents ul li ul li ul li {
    margin-bottom: 20px;
    width: 100%;
    margin-right: 10px;
  }

  .site-footer {
    position:fixed;
  }
}

.menu_active {
  right: 0;
}