@keyframes loading-scale {
    0% {
        transform: scale(1);
        opacity: 1;
    }

    45% {
        transform: scale(0.1);
        opacity: 0.7;
    }

    80% {
        transform: scale(1);
        opacity: 1;
    }
}

.loading {
    position: fixed;
    top: 50%;
    left: 50%;
    margin-top: -20px;
    margin-left: -60px;
    width: 128px;
    height: 40px;
    z-index: 1001;

    > div {
        $init: 0.12;

        @for $i from 1 to 3 {
            &:nth-child($i) {
                animation: loading-scale 0.75s $(init)s infinite cubic-bezier(0.2, 0.68, 0.18, 1.08);
            }

            $init: calc(($i + 1) * 0.12);
        }

        display: inline-block;
        margin: 4px;
        width: 30px;
        height: 30px;
        border-radius: 100%;
        background: #fff;
    }
}