/* 定制公告栏文字信息 */
.gonggao{
    text-align: center;
    font-size:60px;
    color:blue;
}
.wenzi{
    text-align: center;
    font-size:75px;
}
/* 定制博客背景图片，url里面是你的图片位置信息 */
body { 
     background-color: #efefef;
     background-image:url(https://i.loli.net/2021/08/10/sA85RDI9Yqvy72C.jpg); 
     background-repeat: no-repeat; 
     background-attachment: fixed; 
     background-position: center 0; 
     background-size: cover; 
    padding-top:0px;
    opacity:0.9; 
    filter:Alpha(opacity=90);
  }