Markdown accepts the raw HTML and passes it unchanged, so define your "stylized" elements as HTML:
<h2 style="color: red;">Header 1</h2>
, HTML ( - , HTML), .
Markdown, , ( ):
## Header 1 {style="color: red;"}
.
, HTML <style> <head> . HTML-, <style> ( @user5219763 ):
---
title: "test"
output:
html_document
---
<style>
#header1 {
color: red;
}
</style>
## Header 1 {#header1}
But how to change style with internal css?