@media screen and (min-width:769px) {
    
    .two li{
        width: 400px;
    }
    
    .twoimg{
        margin-left: 50px;
    }
    
    
    .three_4{
        background: #f0f0f0;
    }

    .center_4{
        height: 81%; 
        display:flex;
    }
    
    .three_4 .title{
        font-size: 2.25rem;
        font-family: PingFang SC, PingFang SC-500;
        font-weight: bold;
        text-align: center;
        color: #000000;
        text-align: center;
        padding-top: 50px;
        line-height: 35px;
    }
    
    .col-md-4{
        width: 33.33333333%;
        min-height: 1px;
        padding-left: 15px;
        padding-right: 15px;
    }
    
    
    .item {
        margin-bottom: 40px;
        min-height: 540px;
        background-color: #fff;
    }
    .item .img{
        height: 270px;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        position: relative;
    }
    
    .item a{
        text-decoration: none;
        color: #191919;
    }
    
    .item .title{
        margin-top: 25px;
        font-size: 24px;
        font-weight: bold;
        color: #191919;
        padding: 0 20px;
        overflow: hidden;
        text-overflow: ellipsis;
        display: -webkit-box;
        -webkit-box-orient: vertical;
        -webkit-line-clamp: 3;
        text-align: left;
    }
    
    .item .date {
        font-size: 16px;
        color: #2793FF;
        margin-top: 15px;
        margin-bottom: 12px;
        padding: 0 20px;
    }
    
    .item .des {
        font-size: 16px;
        color: #888888;
        line-height: 24px;
        overflow: hidden;
        text-overflow: ellipsis;
        display: -webkit-box;
        -webkit-box-orient: vertical;
        -webkit-line-clamp: 3;
        padding: 0 20px;
    }
    
    .bottom a{
        text-decoration: none;
        color: #2793ff;
    }
    .bottom{
        font-size: 16px;
        font-family: PingFang SC, PingFang SC-500;
        font-weight: normal;
        text-align: center;
        color: #2793ff;
        vertical-align: middle;
    }
    .bottom-part {
        text-align: center;
    }
    .bottom-part .read-more{
        padding: 8px 26px;
        border-radius: 4px;
        background-color: #007bff;
        color: #fff;
        text-decoration: none;
    }
}

@media screen and (max-width:769px) {
    
    .three_4{
        background: #f0f0f0;
    }

    .center_4{
        height: 81%;
        padding-bottom: 0; 
    }
    
    .three_4 .title{
        font-size: 2.25rem;
        font-family: PingFang SC, PingFang SC-500;
        font-weight: bold;
        text-align: center;
        color: #000000;
        text-align: center;
        padding-top: 50px;
        line-height: 35px;
    }
    
    .col-md-4{
        width: 100%;
        min-height: 1px;
        margin: 0 auto;
        padding: 0;
    }
    
    
    .item {
        margin-bottom: 40px;
        min-height: 540px;
        background-color: #fff;
    }
    .item .img{
        height: 270px;
        background-repeat: no-repeat;
        background-size: cover;
        background-position: center;
        position: relative;
    }
    
    .item a{
        text-decoration: none;
        color: #191919;
    }
    
    .item .title{
        margin-top: 25px;
        font-size: 24px;
        font-weight: bold;
        color: #191919;
        padding: 0 20px;
        overflow: hidden;
        text-overflow: ellipsis;
        display: -webkit-box;
        -webkit-box-orient: vertical;
        -webkit-line-clamp: 3;
        text-align: left;
    }
    
    .item .date {
        font-size: 16px;
        color: #2793FF;
        margin-top: 15px;
        margin-bottom: 12px;
        padding: 0 20px;
    }
    
    .item .des {
        font-size: 16px;
        color: #888888;
        line-height: 24px;
        overflow: hidden;
        text-overflow: ellipsis;
        display: -webkit-box;
        -webkit-box-orient: vertical;
        -webkit-line-clamp: 3;
        padding: 0 20px;
    }
    
    .bottom a{
        text-decoration: none;
        color: #2793ff;
    }
    .bottom{
        font-size: 16px;
        font-family: PingFang SC, PingFang SC-500;
        font-weight: normal;
        text-align: center;
        color: #2793ff;
        vertical-align: middle;
        padding-bottom: 10px
    }
    .bottom-part {
        text-align: center;
    }
    .bottom-part .read-more{
        padding: 8px 26px;
        border-radius: 4px;
        background-color: #007bff;
        color: #fff;
        text-decoration: none;
    }
}