查看“︁MediaWiki:Common.css”︁的源代码

/* 模板来自MCBBS Wiki */
/* info类模板 */
.infoBox {
    margin: 0 auto;
}
.infoBoxTitle {
    margin: 3px auto;
    padding: 0;
    text-align: center;
    font-weight: 700;
}
.infoBoxIcon {
    display: table-cell;
    padding: 2px 0 2px .5em;
    vertical-align: middle;
}
.infoBoxText {
    display: table-cell;
    padding: .25em .5em .25em 1.3em;
    width: 100%;
    vertical-align: middle;
}
.infoBoxContent {
    border: 1px solid #ddd;
    border-left-width: 0;
    background: #fbfbfb;
}
.infoBoxBelow {
    margin: 0 auto;
    padding: 0;
    text-align: center;
}

/* 顶部轮播文字 */
.topsign{
    position: relative;
    width: 100%;
    height: 65px;
    overflow: hidden;
}

.topsign .topsignitem{
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: auto;
}

.topsign .topsignitem p{
    line-height: 50px;
    text-align: center;
}

/* 背景图 */
<body background="bj.jpg" style="background-attachment:fixed";> 
body {
background:url(/www/wwwroot/mcserver.wiki/images/17412311.png);//背景路径

background-size:100%;//填充

background-repeat:no-repeat;//无重复

background-attachment: fixed;//固定

}