.banner {
  position: relative;
  width: 100%;
  overflow: hidden;
  height: auto;
}
.banner .banner_wrap {
  width: 100%;
  padding-bottom: 31.25%;
}
.banner .banner_wrap > img {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
}
.banner .on_banner {
  position: absolute;
  top: 50%;
  -webkit-transform: translateY(-50%);
  transform: translateY(-50%);
  left: 0;
  width: 100%;
  color: #fff;
}
.banner .on_banner .onbanner_tit {
  font-size: 40px;
  font-weight: 500;
  text-align: center;
}
.content {
  padding-top: 146px;
}
.content .left_menu {
  width: 17.5%;
  float: left;
}
.content .left_menu .menu_li {
  color: rgba(34, 34, 34, 0.5);
  margin-bottom: 24px;
  font-weight: 400;
  cursor: pointer;
}
.content .left_menu .menu_li.cur {
  color: #222222;
  font-weight: 500;
  position: relative;
}
.content .left_menu .menu_li.cur:before {
  content: "";
  position: absolute;
  display: block;
  width: 4px;
  height: 100%;
  background: #000;
  left: -15px;
}
.content .right_content {
  width: 82.5%;
  float: left;
}
.content .right_content .content_area {
  display: none;
}
.content .right_content .content_area.cur {
  display: block;
}
.content .right_content .content_item {
  margin-bottom: 60px;
}
.content .right_content .content_tit {
  font-size: 24px;
  font-weight: 500;
  padding-bottom: 20px;
  border-bottom: 1px solid rgba(34, 34, 34, 0.3);
  margin-bottom: 15px;
}
.content .right_content .content_tit > span {
  font-size: 16px;
  margin-left: 20px;
}
.content .right_content .content_dec {
  font-size: 18px;
  font-weight: 400;
  line-height: 1.8em;
  color: #666;
}
.content .right_content .content_dec p {
  margin-bottom: 20px;
}
.content .right_content .mailto {
  font-size: 16px;
  font-weight: 400;
  margin-bottom: 58px;
}
.content .right_content .mailto > a {
  color: #eb8d10;
}
@media only screen and (max-width: 768px) {
  .content .right_content .content_tit {
    font-size: 18px;
  }
  .content .right_content .content_dec {
    font-size: 12px;
  }
}
@media only screen and (max-width: 500px) {
  .banner {
    display: none;
  }
  .content .left_menu,
  .content .right_content {
    width: 100%;
  }
  .content .left_menu .menu_li {
    display: block;
    float: left;
    width: 40%;
    margin: 0 5%;
    text-align: center;
    height: 40px;
    line-height: 40px;
    border-radius: 20px;
    border: 1px solid rgba(34, 34, 34, 0.5);
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
    margin-bottom: 30px;
  }
  .content .left_menu .menu_li.cur:before {
    display: none;
  }
  .content .left_menu .menu_li.cur {
    background: #000;
    border: none;
    color: #fff;
  }
  .content {
    padding-top: 60px;
  }
}