.kb_black_overlay {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    z-index: 100;
}
.kb_img {
    cursor: pointer;
}
.kb_enlarge_container {
    display: none;
}
.kb_enlarge_preview_img {
    /*这里我设置的是：预览后放大的图片相对于整个页面定位*/
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    /*宽度设置为页面宽度的70%，高度自适应*/
    width: 70%;
    z-index: 200;
}
/*关闭预览*/
.kb_close {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    cursor: pointer;
    z-index: 200;
}