/* @import url('https://fonts.cdnfonts.com/css/eurostile-2'); */

body {
  counter-reset: section;
}
img {
  margin: 0 auto;
}
h2 {
  counter-reset: subsection;
}
h2::before {
  counter-increment: section;
  content: "Section " counter(section) ". ";
}
h3::before {
  counter-increment: subsection;
  content: counter(section) "." counter(subsection) " ";
}
h4::before {
  counter-increment: thirdsection;
  content: counter(section) "." counter(subsection) "." counter(thirdsection) " ";
}
div.post > h2::before,
div#leftmenu h3::before {
  content: none;
}
#back-top {
    position: fixed;
    bottom: 10px;
    right: 5px;
    z-index: 99;
}
#back-top span {
    width: 100px;
    height: 100px;
    display: block;
    background:url(https://www.cnblogs.com/images/cnblogs_com/guomie/1464522/o_123.png) no-repeat center center;
    background-size: contain;
}
#back-top a{outline:none}