CSS3实现加载页面时的网页淡入效果

body{
    -webkit-animation: bgbody 3s ease;
    -o-animation: bgbody 3s ease;
    animation: bgbody 3s ease;
}
@keyframes bgbody {
    0%{
        opacity: 0;
        background-color: #ffffff;
    }
    100%{
        opacity: 1;
    }
}