.page .topics_cont_out > .topics_list {
    display: flex;
    flex-wrap: wrap;
    margin-top: 20px;
}
.page .topics_list > .topic_item_out {
    margin-left: 24px;
    width: calc((100% - 48px) / 3);
}
.page .topics_list > .topic_item_out:nth-child(n + 4) {
    margin-top: 24px;
}
.page .topics_list > .topic_item_out:nth-child(3n + 1) {
    margin-left: 0;
}

/* 移动端适配 */
@media screen and (max-width: 800px) {
    .page .topics_cont_out {
        padding: 0 10px;
    }
    .page .topics_list > .topic_item_out {
        margin-left: 0;
        padding-bottom: 20px;
        width: 100%;
    }
    .page .topics_list > .topic_item_out + .topic_item_out {
        border-top: 1px solid #ddd;
        padding-top: 20px;
    }
    .page .topics_list > .topic_item_out h4.title {
        margin-top: 0;
    }
}