@keyframes swing {

    20% {
    transform: rotate3d(0, 0, 1, 15deg);
    }

    40% {
    transform: rotate3d(0, 0, 1, -10deg);
    }

    60% {
    transform: rotate3d(0, 0, 1, 5deg);
    }

    80% {
    transform: rotate3d(0, 0, 1, -5deg);
    }

    100% {
    transform: rotate3d(0, 0, 1, 0deg);
    }

}

.swing {
animation-duration: 1s;
animation-name: swing;
transform-origin: top center;
animation-fill-mode: both;
}