.span-tip {
    position: absolute;
    left: 50%;
    top: 50%;
    min-width: 20px;
    padding: 20px;
    line-height: 20px;
    margin-top: -0.2rem;
    margin-left: -1.25rem;
    border-radius: 10px;
    font-size: 20px;
    text-align: center;
    color: #fff;
    background: #000;
    z-index: 9999;
    opacity: 0.9;
}