概述
在使用Typora写比较长的文章时，需要给章节编号，方便区分层次。如果手动编号，一旦章节顺序改变，很多章节的编号都需要一一手动修改，极其麻烦。
Typora官方提供了自动编号的方法：https://support.typora.io/Auto-Numbering/。本文将对官方提供的方法，以及简单改进进行介绍。
原理
这个方法的原理是，Typora基于浏览器开发（使用快捷键Shift+F12可以打开开发者工具）。因此，可以利用CSS实现自动编号。
具体操作
打开Typora -> 文件 -> 偏好设置 -> 外观 -> 打开主题文件夹。
在主题文件夹下新建文件base.user.css。
将https://support.typora.io/Auto-Numbering/中提供的三份代码（分别实现文章内容自动编号、TOC自动编号、侧边栏大纲自动编号）复制到base.user.css中。
重启Typora。
改进
官方提供的代码会对一级标题进行编号，但实际写文章时，一级标题往往是文章标题，无需编号，因此，我对代码进行了简单修改。下面是修改后的代码：
文章内容自动编号：
/** initialize css counter */
h1 {
counter-reset: h2
}
h2 {
counter-reset: h3
}
h3 {
counter-reset: h4
}
h4 {
counter-reset: h5
}
h5 {
counter-reset: h6
}
/** put counter result into headings */
#write h2:before {
counter-increment: h2;
content: counter(h2) ". "
}
#write h3:before,
h3.md-focus.md-heading:before /** override the default style for focused headings */ {
counter-increment: h3;
content: counter(h2) "." counter(h3) ". "
}
#write h4:before,
h4.md-focus.md-heading:before {
counter-increment: h4;
content: counter(h2) "." counter(h3) "." counter(h4) ". "
}
#write h5:before,
h5.md-focus.md-heading:before {
counter-increment: h5;
content: counter(h2) "." counter(h3) "." counter(h4) "." counter(h5) ". "
}
#write h6:before,
h6.md-focus.md-heading:before {
counter-increment: h6;
content: counter(h2) "." counter(h3) "." counter(h4) "." counter(h5) "." counter(h6) ". "
}
/** override the default style for focused headings */
#write>h3.md-focus:before,
#write>h4.md-focus:before,
#write>h5.md-focus:before,
#write>h6.md-focus:before,
h3.md-focus:before,
h4.md-focus:before,
h5.md-focus:before,
h6.md-focus:before {
color: inherit;
border: inherit;
border-radius: inherit;
position: inherit;
left:initial;
float: none;
top:initial;
font-size: inherit;
padding-left: inherit;
padding-right: inherit;
vertical-align: inherit;
font-weight: inherit;
line-height: inherit;
}
TOC自动编号：
/* No link underlines in TOC */
.md-toc-inner {
text-decoration: none;
}
.md-toc-h1 {
margin-left: 0;
font-size: 1.5rem;
counter-reset: h2toc
}
.md-toc-h2 {
font-size: 1.1rem;
margin-left: 2rem;
counter-reset: h3toc
}
.md-toc-h3 {
margin-left: 3rem;
font-size: .9rem;
counter-reset: h4toc
}
.md-toc-h4 {
margin-left: 4rem;
font-size: .85rem;
counter-reset: h5toc
}
.md-toc-h5 {
margin-left: 5rem;
font-size: .8rem;
counter-reset: h6toc
}
.md-toc-h6 {
margin-left: 6rem;
font-size: .75rem;
}
.md-toc-h2:before {
color: black;
counter-increment: h2toc;
content: counter(h2toc) ". "
}
.md-toc-h2 .md-toc-inner {
margin-left: 0;
}
.md-toc-h3:before {
color: black;
counter-increment: h3toc;
content: counter(h2toc) ". " counter(h3toc) ". "
}
.md-toc-h3 .md-toc-inner {
margin-left: 0;
}
.md-toc-h4:before {
color: black;
counter-increment: h4toc;
content: counter(h2toc) ". " counter(h3toc) ". " counter(h4toc) ". "
}
.md-toc-h4 .md-toc-inner {
margin-left: 0;
}
.md-toc-h5:before {
color: black;
counter-increment: h5toc;
content: counter(h2toc) ". " counter(h3toc) ". " counter(h4toc) ". " counter(h5toc) ". "
}
.md-toc-h5 .md-toc-inner {
margin-left: 0;
}
.md-toc-h6:before {
color: black;
counter-increment: h6toc;
content: counter(h2toc) ". " counter(h3toc) ". " counter(h4toc) ". " counter(h5toc) ". " counter(h6toc) ". "
}
.md-toc-h6 .md-toc-inner {
margin-left: 0;
}
侧边栏大纲自动编号：
.outline-h1 {
counter-reset: h2
}
.outline-h2 {
counter-reset: h3
}
.outline-h3 {
counter-reset: h4
}
.outline-h4 {
counter-reset: h5
}
.outline-h5 {
counter-reset: h6
}
.outline-h2>.outline-item>.outline-label:before {
counter-increment: h2;
content: counter(h2) ". "
}
.outline-h3>.outline-item>.outline-label:before {
counter-increment: h3;
content: counter(h2) "." counter(h3) ". "
}
.outline-h4>.outline-item>.outline-label:before {
counter-increment: h4;
content: counter(h2) "." counter(h3) "." counter(h4) ". "
}
.outline-h5>.outline-item>.outline-label:before {
counter-increment: h5;
content: counter(h2) "." counter(h3) "." counter(h4) "." counter(h5) ". "
}
.outline-h6>.outline-item>.outline-label:before {
counter-increment: h6;
content: counter(h2) "." counter(h3) "." counter(h4) "." counter(h5) "." counter(h6) ". "
}
效果图
