body{background:#fff}
.banner {
    height: 100vh;
    width: 100%;
    
    background-size: cover;
    background-repeat:no-repeat;
    background-position:center;
    position: relative;
}
.title {
    color: #fff;
    text-align: center;
    width: 100%;
    position: absolute;
    bottom: 5%;
}
.chTitle {
    font-size: 2rem;
}
.engTitle {
    letter-spacing: 9px;
    font-size: 0.5rem;
    text-transform: uppercase;
    font-family: "AlibabaSans";
}
.arrow-down {
    position: absolute;
    width: 2px;
    z-index: 10;
    left: 50%;
    height: 35px;
    border-radius: 10px;
    bottom: 0;
    background: rgba(255,255,255,.3);
    margin-left: -1px;
    overflow:hidden;
}
.down-line {
    display: inline-block;
    height: 35px;
    width: 2px;
    background: #fff;
    animation: arrow 1.5s ease-in-out infinite;
}
@keyframes arrow {
    0% {
        transform: translateY(-100%);
        -webkit-transform: translateY(-100%);
    }

    to {
        transform: translateY(100%);
        -webkit-transform: translateY(100%);
    }
}
.product-nav {
    background: #f6f6f6;
    justify-content: space-around;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    height: 17rem;
    align-items: center;
}
.nav-item {
    text-align: center;
    width: 15%;
    cursor:pointer;
}
.nav-item p{font-weight:bold;}
.nav-item span{color:#ccc}
.nav-item img{width:100%;}
.product-detail{
    background:#fff;
    padding-bottom:1px;
}
.product-desc {
    text-align: center;
    padding: 8rem 0;
}
.product-detail .desc {
    margin: 4rem 0;
    font-size: 1.15rem;
    line-height:2;
}
.product-item{font-size:0;margin-bottom:15rem;position:relative}
.item-img {
    width: 57%;
    display: inline-block;
    line-height: 0;
    vertical-align: middle;
}
.item-img img{width:100%;}
.text-right, .text-left {
    width: 43%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: absolute;
    top: 0;
    right: 0;
    padding-left: 8.333%;
    opacity: 0;
    background: #f6f6f6;
    height:100%;
}
.text-left{padding-left:16.666%;left:0;}
.text-left+.item-img{margin-left:43%;}
.item-name {
    font-size: 2.25rem;
    font-family: PingFang Heavy;
}
.product-detail .line {
    width: 4rem;
    border-bottom: 3px solid;
    margin: 1.5rem 0;
}
.item-desc {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    line-height:1.75;
}
.item-explain{color:#aaa;font-size:1.1rem;line-height:2}
.explain > div {
    display: inline-block;
    width: 5rem;
    margin-right: 1rem;
}
.explain p {
    font-size: 1rem;
    display: -webkit-box;
    display: -ms-flexbox;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    display: flex;
    justify-content: space-between
}
.product-desc .slogan {
    font-family: PingFang Heavy;
    margin-top: 4rem;
}
.item-type{color:#ccc;font-size:1.1rem;margin-bottom:2rem}
.item-type span{cursor:pointer;padding:.25rem 1.5rem;color:#000;background:#ccc;opacity:.5}
.item-type span.active{color:#fff;background:red;opacity:1}
.item-remind{font-size:1rem;margin-top:2rem;}
.product-title .chTitle {
    font-size: 2rem;
    letter-spacing: 7px;
    margin-top: 1rem;
    text-indent: 7px;
}
.product-title .engTitle{letter-spacing:1px;}