.er{
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: absolute;
    margin: auto;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    font-size: 36px;
    color: #7e7e7e;
}
.er_tips{
    margin-top: 20px;
}
.er_btn{
    margin-top: 30px;
    border: 1px solid black;
    padding: 10px 20px;
    border-radius: 10px;
}
.er .er_btn {
    text-underline: none;
}
a{
    text-decoration: none;
}
.er .btn {
    display: none;
}