body {
    transition: background-color 0.5s;
    margin: 0;
    padding: 0;
    overflow: hidden;
    text-align: center;
}
@keyframes swing {
    0% { transform: rotate(-2deg); }
    50% { transform: rotate(2deg); }
    100% { transform: rotate(-2deg); }
}
#bulb {
    max-height: 50vh;
    transform-origin: top center;
    animation: swing 4s infinite;
    animation-timing-function: ease-in-out;
}