.err-page {
    position: relative;
    height: 100%;

    .err-bg {
        position: absolute;
        height: 200rem / $pxConvertRem;
        width: 200rem / $pxConvertRem;
        top: 50%;
        left: 50%;
        margin-left: -100rem / $pxConvertRem;
        margin-top: -100rem / $pxConvertRem;
        background: image-url('404.png') no-repeat;
        background-size: 100% 100%;
    }
}