.ppt-list {
    width: 100%;
}

    .ppt-list .item {
        position: relative;
        width: 48%;
        padding: 0;
    }

        .ppt-list .item:nth-child(2n) {
            margin-right: 0;
        }

        .ppt-list .item .img-box {
            height: auto;
            width: 100%;
            overflow: auto;
        }

        .ppt-list .item .title {
            height: 0.8rem;
            position: absolute;
            width: 100%;
            bottom: 0;
            left: 0;
            font-size: .32rem;
            background-color: rgba(255, 255, 255, 0.8);
        }

.preparation_pop .pre_cont > div a {
    display: block;
    width: auto;
    height: 0.75rem;
    padding: 0 .6rem;
    background: #f9f9f9;
    border: 0.01rem solid #999999;
    border-radius: .05rem;
    font-size: 0.32rem;
    color: #333;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: .53rem;
    margin-right: 0.4rem;
}