/*样式*/
.txt_img{
    position: relative;}

.txt11{
height: 30px;
    line-height: 30px;
    text-align: center;
    font-size: 14px;
    color: #fff;
    position: absolute;
    bottom: 0;
    left: 0;
    width:100%;
    background: rgba(0, 0, 0, 0.4);}