body:before {
    background: url(https://img2020.cnblogs.com/blog/1407148/202003/1407148-20200331094421271-752501563.png) center/cover no-repeat;
    content: '';
    background-repeat: no-repeat;
    background-position: center;
    opacity: 0.08;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    -webkit-filter: grayscale(40%);
    -moz-filter: grayscale(40%);
    -ms-filter: grayscale(40%);
    -o-filter: grayscale(40%);
    filter: grayscale(40%);
    filter: gray;
}

/*添加按钮*/
.cnblogs-markdown pre {
  position: relative;
}
.cnblogs-markdown pre > span {
  position: absolute;
  top: 0;
  right: 0;
  border-radius: 2px;
  padding: 0 10px;
  font-size: 12px;
  background: rgba(0, 0, 0, 0.4);
  color: #fff;
  cursor: pointer;
}
.cnblogs-markdown pre > .copyed {
  background: #67c23a;
}