.bd{
    width: 100%;
    overflow: hidden;
    height: calc(100% - 70px);
}
.link-content{
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: rgba(0,0,0,.5);
    padding: 15px 0;
    position: absolute;
    bottom:70px;
    z-index: 200;
}