.header-position {
    height: 4.375rem;
}
header {
    background-color: rgba(21, 53, 178, .9);
}
.banner {
    position: relative;
    width: 100%;
    height: 31.5292rem;
    padding-top: 7.25rem;
    padding-left: 7.75rem;
    background: url('http://static.web3di.com/img/3_pic2@2x.jpg') no-repeat center;
    background-size: 100% 100%;
    color: #ffffff;
}
.banner-nav{
    width: 100%;
    height: 3.125rem;  
    background:rgba(43,48,59,.3);
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
}

.banner-nav ul {
    display: flex;
    margin: 0 auto;
}

.banner-nav li {
    line-height: 3.125rem;
    width: 10.75rem;
    text-align: center;
    white-space: nowrap;
    cursor: pointer;
}

.nav-active {
    background: linear-gradient(90deg, rgba(51, 102, 255, 1) 0%, rgba(51, 153, 254, 1) 100%);
}

.banner-nav li:hover {
    background: linear-gradient(90deg, rgba(51, 102, 255, 1) 0%, rgba(51, 153, 254, 1) 100%);
}

.cases {
    position: relative;
    padding: 5.25rem 0;
    background-color: #F9F9F9;
}
.all-case-nav {
    position: absolute;
    left: 50%;
    top: 2.5rem;
    transform: translateX(-50%);
}
.all-case-nav ul {
    display: flex;
    justify-content: space-between;
    font-size:20px;
}
.all-case-nav ul li{
    padding: 0 1rem;
    white-space: nowrap;
    cursor: pointer;
}

.banner-nav .sub-case-nav{
    display: none;
    position: absolute;
    left: 50%;
    top: 4rem;
    transform: translateX(-50%);
    color: #000000;
    z-index:100;
    justify-content: center;
}
.banner-nav .sub-case-nav li{
    width:auto;
    padding: 0 1rem;
}
.banner-nav .sub-case-nav-show{
    display:flex;
}
.banner-nav .sub-case-nav li:hover {
    background: none;
    color: #3385FF;
}
.banner-nav .sub-case-nav .nav-active {
    background: none;
    color: #3385FF;
}
.all-content {
    width: 88.75rem;
    display: flex;
    flex-wrap: wrap;
    /* justify-content: space-between; */
    margin: 0 auto;
}
.case-item {
    width: 21.25rem;

    border-radius:4px;
    margin-top: 1.25rem;
    margin-right: 1.25rem;
    background: #ffffff;
}
.case-item:nth-child(4n){
    margin-right: 0;
}
.case-item img {
    width: 21.25rem;
    height: 14.125rem;
    border-radius: 4px 4px 0 0;
}
.case-item-content {
    padding: 0 1.25rem 1.0rem;
    background: #ffffff;
}
.case-item h4 {
    margin: 15px 0;
    font-size: 1rem;
    line-height: 27px;
    color: #000000;
}
.case-item-info {
    font-size: .875rem;
    color:rgba(153,153,153,1);
}
.loadmore {
    display: none;
}
@media screen and (max-width: 750px) {
    .banner {
        width: 100%;
        height: 22.75rem;
    
    }
    .banner-nav ul {
        width: 46.875rem; 
        height: 4.375rem;
    }
    .banner-nav {
        bottom: 0;
        left: 0;
        height: 4.375rem;
        transform: none;
    }
    .banner-nav ul li {
        width: 11rem;
        height: 4.375rem;
        line-height: 4.375rem;
    }
    .footer-top {
        height: 35rem!important;
    }
    .all-content,
    .content-all {
        width: 41.875rem;
    }
    .case-nav {
        width: 41.875rem;
        top: 1.25rem ;

    }
    .case-nav ul {
        width: 100%;
    }
    .case-item {
        width: 20.25rem;
        border-radius:4px;
        margin-top: 1.25rem;
    }
    .case-item:nth-child(2n){
        margin-right: 0;
    }
    .case-item img{
        width: 20.25rem;
        height: 13.4603rem;
    }
    .case-item-info {
        display: none;
    }
    .loadmore {
        font-size: 1.375rem;
        color: #C1C1C1;
        text-align: center;
    }
    .loadmore img {
        width: 1.5rem;
        height: 1.5rem;
        vertical-align: middle;
        margin-left: .625rem;
    }
}