@media (max-width:1200px) {
     body{
        padding-bottom: 230px;
    }
}
@media (max-width:992px) {
    .page_top_nav {
        float: none;
        margin-top: 10px;
    }
    .page_top_nav li {
        float: none;
        display: block;
    }
    .page_top_nav li a{
        border-right: 0;
        border-bottom: 1px solid #818a91;
        padding: 0 ;
        line-height: 45px;
    }
}
@media (max-width:768px) {
    body{
        padding-bottom: 255px;
    }
    .top_head_nav {
        background: #F0F0F0;
        display: block;
        float: left;
        width: calc(100% - 53px);
        padding: 0 15px 15px;
    }
    .top_head_nav li{
        float: none;
        margin: 0;
        border-bottom: 1px solid #DDD;
    }
    .top_head_nav li a::after,
    .top_head_nav li a::before{
        display: none;
    }
    .main_head_cat li a span{
        width: 125px;
        height: 125px;
        line-height: 80px;
    }
    .box_img{
        margin-bottom: 10px;
        text-align: center;
    }
    .footer_social {
        float: none;
        display: table;
        margin: 5px auto;
    }
    .bb-custom-wrapper {
      overflow-y: auto;
      width: 100%;
    }
    .sidebar_menu{
        width: 200px;
    }
    .bb-bookblock{
        width: 800px;
    }
    .bb-custom-wrapper.b_menu_show .bb-bookblock {
      margin-right: 200px;
      width: 800px;
    }
}
@media (max-width:544px) {
    body{
        padding-bottom: 0;
    }
    footer{
        position: static;
        margin-top: 20px;
    }
    .main_head_cat{
        text-align: center;
        display: block;
    }
     .main_head_cat li{
        margin: 10px auto;
         float: none;
    }
    .top_app{
        width: 46%;
        margin-bottom: 10px;
        font-size: 10px;
    }
    .menu_nav{
        margin-right: 18px;
    }
    .menu_nav li a{
        font-size: 14px;
    }
    .home_books_tab li a.active  {
        margin-left: 0;
        border-left: 1px solid #868686 ;
    }
    .book_head span{
        float: none;
        text-align: center;
    }
}
@media (max-width:480px) {
    .page_top_logo{
        float: none;
    }
    .page_menu_btn {
      display: block;
      margin: 15px auto 0;
        float: none;
    }
    .menu_nav {
      margin-right: 12px;
    }
}