@include u-keyframes(ping) {
    0% {
        @include u-transform(scale(0));
    }
    100% {
        @include u-transform(scale(1));
        opacity: 0;
    }
}

@mixin ping($duration: 1.5s, $delay: 0s, $fill-mode: none, $count: infinite, $timing: ease-in-out) {
    @include u-animation(ping $count $duration $delay $fill-mode $timing);
}