有序列表 CSS 样式包括父编号

我们希望使用 CSS 创建一个如下所示的有序列表：

A.
A.1
A.2
B.
C.
C.1
C.2
C.2.1
C.2.2

您如何将父索引包含在子索引中？

你需要使用CSS 计数器 https://developer.mozilla.org/en-US/docs/counters.

例子 （from MDN https://developer.mozilla.org/en-US/docs/counters)

CSS:

ol {
  counter-reset: section;                /* Creates a new instance of the
                                            section counter with each ol
                                            element */
  list-style-type: none;
}
li:before {
  counter-increment: section;            /* Increments only this instance
                                            of the section counter */
  content: counters(section, ".") " ";   /* Adds the value of all instances
                                            of the section counter separated
                                            by a ".". */
}

HTML:

<ol>
 <li>Entry
 <li>Entry
 <li>Entry with subentries
  <ol>
    <li>Entry
    <li>Entry
    <li>Entry
    <li>Entry
  </ol>
 <li>Entry
 <li>Entry
 <li>Entry with subentries
  <ol>
    <li>Entry
    <li>Entry
    <li>Entry
    <li>Entry
  </ol>
</ol>

JSFiddle http://jsfiddle.net/8MWdL/1/