.err-page {
    .err-bg {
        position: fixed;
        height: 5rem;
        width: 5rem;
        top: 50%;
        left: 50%;
        margin-left: -2.5rem;
        margin-top: -2.5rem;
        background: resolve('common/404.png') no-repeat;
        background-size: 100% 100%;
    }
}