#earth {
    position: fixed;
    top: 5%;
    right: 5%;
    width: 15vw;
    height: 15vw;
    border-radius: 50%;
    background: url('earth.gif') no-repeat center center;
    background-size: cover;
    box-shadow: 0 0 20px rgba(0, 100, 255, 0.7);
    transform-origin: center center;
    animation: pulse 4s infinite ease-in-out;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}