p#back-to-top {
    position: fixed;
    display: none;
    bottom: 100px;
    right: 30px;
}

p#back-to-top a {
    text-align: center;
    text-decoration: none;
    color: #d1d1d1;
    display: block;
    width: 64px;
    /*使用CSS3中的transition属性给跳转链接中的文字添加渐变效果*/
    -moz-transition: color 1s;
    -webkit-transition: color 1s;
    -o-transition: color 1s;
}

p#back-to-top a:hover {
    color: #979797;
}

p#back-to-top a span {
    background-image: url(/html/images/Go-Top.png);
    border-radius: 6px;
    display: block;
    height: 54px;
    width: 46px;
    margin: 0 auto;
    /*使用CSS3中的transition属性给<span>标签背景颜色添加渐变效果*/
    -moz-transition: background 1s;
    -webkit-transition: background 1s;
    -o-transition: background 1s;
    background-size: 100% 100%;
}