*,*::after,*::before {
    box-sizing: border-box;
    -webkit-box-sizing: border-box;
    -ms-box-sizing:border-box;
    -moz-box-sizing: border-box;
}
body {
    font-family: arial;
    font-size: 16px;
    margin: 0;
    background: #fff;
    color: #000;
}
.main_container {
    /* height: 100vh;
    width: 100%;     */
    /* background: url("https://source.unsplash.com/5867BKGyCu4/2400x1600");*/
    background-size: cover;
    background-position: center bottom; 
    position: relative;
    overflow: hidden;
}
.snow,.snow:after,.snow::before {
    content: '';
    position: absolute;
    top: -650px;
    right: 0;
    bottom: 0;
    left: 0;
    background-image: radial-gradient(4px 4px at 100px 50px,#fff,transparent),
                      radial-gradient(6px 6px at 200px 150px, #fff,transparent),
                      radial-gradient(3px 3px at 300px 250px,#fff,transparent),
                      radial-gradient(4px 4px at 400px 350px,#fff,transparent),
                      radial-gradient(6px 6px at 500px 100px,#fff,transparent),
                      radial-gradient(3px 3px at 50px 200px,#fff,transparent),
                      radial-gradient(4px 4px at 150px 300px,#fff,transparent),
                      radial-gradient(6px 6px at 250px 400px,#fff,transparent),
                      radial-gradient(3px 3px at 350px 500px,#fff,transparent),
                      radial-gradient(4px 4px at 550px 550px,#fff,transparent);
    background-size: 650px 650px;
    animation: SnowAnim 3s linear infinite;
}
.snow:after {
    margin-left: -250px;
    opacity: 0.5;
    filter: blur(2px);
    animation-direction: reverse;
    animation-duration: 6s;
}
.snow::before {
    margin-left: -350px;
    opacity: 0.7;
    filter: blur(1px);
    animation-direction: reverse;
    animation-duration: 9s;
}
@keyframes SnowAnim {
    from {
        transform: translateY(0);
    }
    to {
        transform: translateY(650px);
    }
}