.rung {
    animation: rung-bell 2s ease infinite;
}
    
@-webkit-keyframes rung-bell {
    0% {
        -webkit-transform: rotate(0) scale(1) skew(1deg);
    }
    10% {
        -webkit-transform: rotate(-25deg) scale(1) skew(1deg);
        }
    20% {
        -webkit-transform: rotate(25deg) scale(1) skew(1deg);
    }
    30% {
        -webkit-transform: rotate(-25deg) scale(1) skew(1deg);
    }
    40% {
        -webkit-transform: rotate(25deg) scale(1) skew(1deg);
    }
    50% {
        -webkit-transform: rotate(0) scale(1) skew(1deg);
    }
    100% {
        -webkit-transform: rotate(0) scale(1) skew(1deg);
    }
}