如何在RMarkdown的PDF与HTML中实现runin及bfseries章节标题样式

output:
html_document:
toc: no
keep_md: no
pdf_document:
latex_engine: pdflatex
keep_tex: no
header-includes:

• \usepackage{lipsum}
• \usepackage{titlesec}
• \titleformat{\section}[runin]{\bfseries}{}{0em}{}
• \titlespacing{\section}{0pt}{*3}{2ex}
• \titleformat{\subsection}[runin]{\bfseries}{}{0em}{}
• \titlespacing{\subsection}{0pt}{*1}{2ex}

/* HTML端样式调整：实现runin和粗体 */
h1, h2 {
  display: inline-block; /* 将块级标题改为行内块，实现与正文同行 */
  font-weight: bold; /* 粗体效果，替代手动添加** */
  font-size: 20px; 
  color: black;
  margin-right: 1em; /* 标题与正文之间添加间距，避免拥挤 */
  margin-top: 1em; /* 保持标题上方的空白，和PDF端排版一致 */
}
body{font-size: 20px;}
/* 确保标题后的正文不会被异常换行 */
h1 + p, h2 + p {
  display: inline;
}

knitr::opts_chunk$set(echo = TRUE)

In Section 14.2.6 we discuss the use of CART or PRIM for constructing generalized association rules. Show that a problem occurs with either of these methods when we generate the random data from the productmarginal distribution; i.e., by randomly permuting the values for each of the variables. Propose ways to overcome this problem.

Solution #

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\lipsum[1]

Cluster the demographic data of Table $14.1$ using a classification tree. Specifically, generate a reference sample of the same size of the training set, by randomly permuting the values within each feature. Build a classification tree to the training sample (class 1 ) and the reference sample (class 0 ) and describe the terminal nodes having highest estimated class 1 probability. Compare the results to the PRIM results near Table $14.1$ and also to the results of $K$-means clustering applied to the same data.

Solution #

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\lipsum[2]

### 关键说明
1. **HTML端核心CSS调整**
   - `display: inline-block`：将默认是块级元素的h1、h2改为行内块，让标题能和后续正文处于同一行
   - `font-weight: bold`：直接实现粗体效果，无需手动给标题文本加`**`标记
   - `margin-right: 1em`：给标题和正文之间设置合适间距，避免排版拥挤
   - `h1 + p, h2 + p {display: inline}`：确保标题紧跟的段落也保持行内显示，不会被强制换行

2. **PDF端保持原有设置**
   你之前用`titlesec`包配置的`\titleformat{\section}[runin]{\bfseries}{}{0em}{}`等代码已经完美实现PDF端的runin和粗体需求，无需修改。

内容的提问来源于stack exchange，提问作者John Stone