#snow-container {
    height: 120vh;
    z-index: -5;
    overflow: hidden;
    position: fixed;
    top: 0;
    transition: opacity 500ms;
    width: 100%;
}
.snow {
    animation: fall ease-in infinite, sway ease-in-out infinite;
    color: skyblue;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    position: absolute;
    background-color: white;
}
@keyframes fall {
    100% {
        top: 100vh;
    }
}

@keyframes sway {
    0% {
        margin-left: 0;
    }
    25% {
        margin-left: 50px;
    }
    50% {
        margin-left: -50px;
    }
    75% {
        margin-left: 50px;
    }
    100% {
        margin-left: 0;
    }
}