我使用的是一个第三方美化工具 cnblogs-theme-silence。里面有很详细的教程。

一、进入设置页面

二、页面定制 CSS 代码框

博客皮肤 必须选择 Custom。

三、博客侧边栏公告（支持HTML代码）

<script>
window.$silence = {
  avatar: "https://pic.cnblogs.com/avatar/2164037/20210211195255.png",
  defaultMode: "light",
  favicon: 'https://s4.aconvert.com/convert/p3r68-cdx67/aeuqh-faq1l.ico',
  navbars: [{
        title: '标签',
        url: 'https://www.cnblogs.com/qiuzhaohai/tag/'
    }],
  catalog: {
    enable: true,
    index: false,
    active: true,
    levels: ["h2", "h3", "h4"],
  },
  signature: {
    enable: true,
    author: null,
    license: [
      "署名-非商业性使用-相同方式共享 4.0 国际",
      "https://creativecommons.org/licenses/by-nc-sa/4.0/",
    ],
  },
  sponsor: {
    enable: true,
    text: "跟随本心",
    wechat: "https://images.cnblogs.com/cnblogs_com/blogs/665147/galleries/1931134/t_210211173855wx_qrcode.jpeg",
    alipay: "https://images.cnblogs.com/cnblogs_com/blogs/665147/galleries/1931134/t_210211173909alipay_qrcode.jpeg",
  },
};
</script>
<script src="https://cdn.jsdelivr.net/gh/esofar/cnblogs-theme-silence@3.0.0-beta3/dist/silence.min.js"></script>

页首 HTML 代码

<div class="light-loading">
  <div class="box">
    <h2>Loading</h2>
    <span></span><span></span><span></span><span></span><span></span><span></span><span></span>
  </div>
</div>