CSS3下雪动画效果

HTML
<div class="header">
  <div class="wrapper">
    <div class="christmas-tree tree1"></div>
    <div class="christmas-tree tree2"></div>
    <div class="christmas-tree tree3"></div>
    <div class="snowman"></div>
    <div class="christmas-tree tree4"></div>
    <div class="christmas-tree tree5"></div>
    <div class="christmas-tree tree6"></div>
  </div>
</div>
CSS
查看页面源代码演示时，您可以找到完整的 CSS3 代码

为了实现下雪的效果，您需要为第一次.header背景background-position属性进行动画处理。作为一个快速说明，浏览器不支持多个背景，雪将不可见此示例。
.header{
margin: 0 0 30px;
    background: url(header-bg.png);
    background: url(snow-bg.png) repeat-y center, url(header-bg.png);
    animation: animate-snow 9s linear infinite;
}
@keyframes animate-snow
{
    0% { background-position: center 0, 0 0;}
    100% { background-position: center 885px, 0 0;}
}

.wrapper元素基本上持有我们圣诞树与雪人。请注意position: relative：
.wrapper{
    width: 960px;
    height: 315px;
    margin: auto;
    overflow: hidden;
    position: relative;
    background: url(wrapper-bg.png) no-repeat bottom;
}
为圣诞树、animation-duration值是随机改变以创建一个很酷的效果：
@keyframes animate-drop {   
    0% {opacity:0;transform: translate(0, -315px);}
    100% {opacity:1;transform: translate(0, 0);}
}
.christmas-tree,
.snowman {
    position: absolute;
    animation: animate-drop 1s linear;
}
.christmas-tree {
    width: 112px;
    height: 137px;
    background: url(christmas-tree.png);
}
.snowman {
    width: 115px;
    height: 103px;
    top: 195px;
    left: 415px;
    background: url(snowman.png);
    animation-duration: .6s;
}
.tree1 {
    top: 165px;
    left: 35px;
    animation-duration: .6s;
}
.tree2 {
    left: 185px;
    top: 175px;
    animation-duration: .9s;
}
.tree3 {
    left: 340px;
    top: 125px;
    animation-duration: .7s;
}
.tree4 {
    left: 555px;
    top: 155px;
    animation-duration: .8s;
}
.tree5 {
    left: 710px;
    top: 170px;
    animation-duration: .7s;
}
.tree6 {
    left: 855px;
    top: 125px;
    animation-duration: .6s;
}