.image-box{
    width: 100%;
    height: 100%;
    position: relative;
    &.onload {
        background: #f2f4f5;
    }
    .image-null{
        width: .25rem;
        height: .4rem;
        line-height: .4rem;
        font-size: .5rem;
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%,-50%);
        -webkit-transform: translate(-50%,-50%);
        color: #fff;
    }
}