.cu-checker {
    animation: shake 1.25s cubic-bezier(.36, .07, .19, .97) both infinite;
    transform: translate3d(0, 0, 0);
    backface-visibility: hidden;
    perspective: 1000px;
}

@keyframes shake {

    10%,
    90% {
        transform: translate3d(-1px, 0, 0);
    }

    20%,
    80% {
        transform: translate3d(1px, 0, 0);
    }

    30%,
    50%,
    70% {
        transform: translate3d(-4px, 0, 0);
    }

    40%,
    60% {
        transform: translate3d(4px, 0, 0);
    }
}