.snowfall {
    width: 100％;
    height: 1410px;
    /*background-color: #393e4f;*/
    background: -moz-linear-gradient(top, #393e4f, #FFF);
    background: -webkit-linear-gradient(top, #393e4f, #FFF);
    background: linear-gradient(to bottom, #393e4f, #FFF);
    z-index:20;
    background-image: url('/snow/snow1.png'),
        url('/snow/snow2.png'),
        url('/snow/snow3.png');
    <!--url('/snow/snow4.gif');-->
    -webkit-animation: snow 100s linear infinite;
    animation: snow 100s linear infinite;
}
@-webkit-keyframes snow {
    0% {background-position: 0 0, 0 0, 0 0;}
    100% {background-position: 0 900px, 0 1410px, 0 600px;}
}
@keyframes snow {
    0% {background-position: 0 0, 0 0, 0 0;}
    100% {background-position: 0 900px, 0 1410px, 0 600px;}
}