@-webkit-keyframes circle {
    0% {
        opacity: 1;
    }

    40% {
        opacity: 1;
    }

    100% {
        width: 200%;
        height: 200%;
        border-radius: 200%;
        opacity: 0;
    }
}

@keyframes circle {
    0% {
        width: 0;
        height: 0;
        opacity: 1;
    }

    40% {
        opacity: 1;
    }

    100% {
        width: 200%;
        height: 200%;
        opacity: 0;
    }
}