.neige {
    z-index: 999999;
    position: fixed;
    top: 0;
    left: 0;

    width: 100vw;
    height: calc(100vh + 200px);
    pointer-events: none;
    overflow: hidden;
}

.flocon {
    position: absolute;
    top: -200px;
    background: rgba(255,255,255,0.9);
    border-radius: 50%;
    box-shadow: 0 0 10px white;

    animation: snowfall var(--takin_duration) linear infinite;
}

@keyframes snowfall {
    0% {
        transform: translateX(var(--takin_xstart)) translateY(-200px);
    }
    100% {
        transform: translateX(var(--takin_xend)) translateY(calc(100vh + 200px));
    }
}