/*：源代码唯一下载地址: https://www.99ziyuan.net*//*** material-scrolltop** Author: Bartholomej* Website: https://github.com/bartholomej/material-scrolltop* Docs: https://github.com/bartholomej/material-scrolltop* Repo: https://github.com/bartholomej/material-scrolltop* Issues: https://github.com/bartholomej/material-scrolltop/issues*/.material-scrolltop {    display: block;    position: fixed;    width: 0;    height: 0;    bottom: 23px;    right: 23px;    padding: 0;    overflow: hidden;    outline: none;    border: none;    border-radius: 2px;    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.5);    cursor: hand;    border-radius: 50%;    background: #000000;    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);    -webkit-transition: all 0.3s cubic-bezier(0.25, 0.25, 0, 1);    -ms-transition: all 0.3s cubic-bezier(0.25, 0.25, 0, 1);    -moz-transition: all 0.3s cubic-bezier(0.25, 0.25, 0, 1);    -o-transition: all 0.3s cubic-bezier(0.25, 0.25, 0, 1);    transition: all 0.3s cubic-bezier(0.25, 0.25, 0, 1);}.material-scrolltop:hover {    background-color: #000000;    text-decoration: none;    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.5), 0 3px 15px rgba(0, 0, 0, 0.5);    outline: none;}.material-scrolltop::before {    position: absolute;    top: 50%;    left: 50%;    -webkit-transform: translate(-50%, -50%);    -ms-transform: translate(-50%, -50%);    -moz-transform: translate(-50%, -50%);    -o-transform: translate(-50%, -50%);    transform: translate(-50%, -50%);    content: "";    width: 0;    border-radius: 100%;    background: #000000;}.material-scrolltop:active::before {    width: 120%;    padding-top: 120%;    -webkit-transition: all 0.2s ease-out;    -ms-transition: all 0.2s ease-out;    -moz-transition: all 0.2s ease-out;    -o-transition: all 0.2s ease-out;    transition: all 0.2s ease-out;}.material-scrolltop.reveal {    width: 56px;    height: 56px;    outline: none;}.material-scrolltop span {    display: block;    font-size: 25px;    color: #fff;}.material-scrolltop,.material-scrolltop::before {    background-image: url("../image/top-arrow.svg");    background-position: center 50%;    background-repeat: no-repeat;    z-index: 999999999;}/*：源代码唯一下载地址: https://www.99ziyuan.net*/