.loading-mask {
    position: fixed;
    background: rgba(0,0,0,.1);
    top: 0;
    bottom: 0;
    right: 0;
    left: 0;
    
    .loading {
        position: absolute;
        width: 100rem / $pxConvertRem;
        height: 40rem / $pxConvertRem;
        background: image-url('loading.gif') no-repeat;
        background-size: 100% 100%;
        top: 50%;
        left: 50%;
        margin-left: -50rem / $pxConvertRem;
        margin-top: -20rem / $pxConvertRem;
    }
}