body {
    margin: 0;
    font-family: 'Arial', sans-serif;
}

#container {
    padding: 20px;
}

#moving-icon {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 36px;
    animation: moveIcon 4s linear infinite;
}

@keyframes moveIcon {
    0% {
        transform: translate(-50%, -50%) translateX(-100px);
    }
    50% {
        transform: translate(-50%, -50%) translateX(100px);
    }
    100% {
        transform: translate(-50%, -50%) translateX(-100px);
    }
}