@media (max-width: 992px) {
  nav {
    display: none;
  }
  #menu_open_btn {
    display: block;
  }
  .item_right_top {
    margin-top: 15px;
  }
  .item_right_center p {
    text-overflow: -o-ellipsis-lastline;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 4;
    line-clamp: 4;
    -webkit-box-orient: vertical;
    color: #505050;
  }
}
@media (max-width: 768px) {
  nav {
    display: none;
  }
  #menu_open_btn {
    display: block;
  }
  .slide-text p {
    font-size: 18px;
    letter-spacing: 5px;
  }
  .product_item {
    width: 50%;
  }
  .product_classif_list li {
    width: 33%;
  }
  .about_text_bottom {
    margin-top: 15px;
  }
  .about_text_top span {
    text-overflow: -o-ellipsis-lastline;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 5;
    line-clamp: 5;
    -webkit-box-orient: vertical;
  }
  .about_text_bottom span:first-child {
    font-size: 16px;
  }
  .icon-jiantou {
    font-size: 30px;
  }
  .case_list_item {
    width: 50%;
    padding: 15px;
  }
  .footer_nav {
    height: auto;
  }
  .phone_number {
    float: left;
    padding: 0 15px;
  }
  .item_right_top p {
    font-size: 24px;
  } 
  .item_right_center {
    margin-bottom: 10px;
  }
}
@media (max-width: 576px) {
  .home_content {
    padding: 0 15px;
  }
  .slide-text p {
    font-size: 18px;
    letter-spacing: 5px;
  }
  .about_img {
    width: 100%;
    max-height: 240px;
    padding: 0 15px;
    box-sizing: border-box;
  }
  .about_text {
    width: 100%;
    margin-top: 15px;
    /* max-height: 200px; */
    /* overflow: hidden; */
  }
  .home_about {
    padding: 100px 15px;
    padding-bottom: 0;
  }
  .case_page_content {
    padding: 0 15px;
  }
  .about_text_top span {
    text-overflow: -o-ellipsis-lastline;
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 7;
    line-clamp: 7;
    -webkit-box-orient: vertical;
  }
  .about_text_bottom {
    margin-top: 15px;
  }
  .about_text_bottom span:first-child {
    font-size: 16px;
  }
  .icon-jiantou {
    font-size: 30px;
  }
  .footer_nav {
    height: auto;
    /* padding: 0 15px; */
  }
  .footer_nav_item {
    display: inline-block;
    width: 50%;
  }
  .phone_number {
    float: left;
  }
  .item_left {
    float: left;
    width: 35%;
    height: auto;
    vertical-align: middle;
    overflow: hidden;
    text-align: center;
  }
  .item_right {
    float: left;
    width: 100%;
    margin-top: 10px;
  }
  .form_group {
    width: 450px;
    /* width: 100%; */
  }
}
@media (max-width: 481px) {
  .slide-text p {
    font-size: 14px;
    letter-spacing: 5px;
    white-space: nowrap;
  }
  .home_content {
    padding: 0 15px;
  }
  .form_group {
    /* width: 350px; */
    width: 100%;
  }
}

@media (min-width: 576px) {
  .content {
    max-width: 540px;
  }
  .home_content {
    width: 100%;
    max-width: 540px;
  }
  
}
@media (min-width: 768px) {
  .content {
    max-width: 720px;
    height: 80px;
  }
  .home_content {
    max-width: 720px;
  }
}

@media (min-width: 992px) {
  .content {
    max-width: 960px;
    height: 80px;
  }
  .home_content {
    max-width: 960px;
  }
}
@media (min-width:1200px) {
  .content {
    max-width: 1140px;
    height: 80px;
  }
  .home_content {
    max-width: 1140px;
  }
}